Ceramic Industry January 2012

January 2012 | Volume 162 | Issue Number 1 www.ceramicindustry.com

DIGITAL EXCLUSIVE SPECIAL SECTION Raw & Manufactured Materials:

2012 Overview

Mark your calendars! St. Louis Section/RCD 48th Annual Symposium: March 28-29, 2012 The St. Louis Section and the Refractory Ceramics Division of The American Ceramic Society will sponsor the 48th Annual Symposium on the theme “Refractories for Non-Ferrous Applications” on March 28-29, 2012. The meeting will be held in St. Louis, Missouri, at the Hilton St. Louis Airport Hotel. Co-program chairs Ben Markel of Resco Products and Rick Solak of Wahl Refractories

The Tabletop Expo format is the same as before with each vendor having a 6-foot table to display products and literature. The charge is $300, which will be used to cover the cost of the Expo Hall and provide an open two hour bar during the “Meet and Greet” for the attendees prior to dinner on Wednesday evening. If you are interested in participating in the Tabletop Expo, contact Patty Smith at (573) 341-6265 [email protected] or Mary Reidmeyer at (573) 341-7519, [email protected]. Please note that a meeting of the ASTM International C-8 Committee on Refractories will be held on March 27th, before this joint St. Louis SectionlRCD conference. Contact Kate McClung at (610) 832-9717 for more information on this meeting. A block of rooms has been set aside for the evenings of March 26-29,2012 at the Hilton (314) 426-5500. The rate is $99.00 for a single or double. To receive the $99 rate mention the Group Name: St. Louis Section of The American Ceramic Society or Group Code: MUS when making your reservation. The web address to make online reservations is http://WWW.hilton.com/en/hi/grOUps/personalizedlS/STLHIHF-MUS-20120326/index. jhtml?WT.mcid=POG. All reservations must be received on or before February 21,2012. For further information please contact Patty Smith at tel: (573) 341-6265, Fax: (573) 341-2071 or email: [email protected].

Imerys Ceramics Driving Innovation for Ceramics worldwide

a Ceramics applications a Global project support a Innovation in ceramics a Mineral processing a Mineral evaluation

World leader in mineral solutions for ceramic manufacturers www.imerys-ceramics.com

Your kiln. Like no other. Your kiln needs are unique, and Harrop’s experienced staff will thoroughly analyze your process and objectives before recommending a final solution. This review often includes precise characterization of your ceramic materials and pilot testing at our in-house facility. After defining the most efficient thermal cycle for your product, Harrop then engineers an energy-efficient, properly sized kiln that is uniquely suited to your operation. Hundreds of customers will tell you that this expert application engineering is what separates Harrop from “cookie cutter” kiln suppliers. Learn more at www.harropusa.com, or call us at 614-231-3621 to discuss your special requirements.

Fire our imagination www.harropusa.com

³ TABLEOFCONTENTS January 2012 | Volume 162 | Issue Number 1

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90

92

DEPARTMENTS

FEATURES

Inside CI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

³Raw & Manufactured Materials: 2012 Overview Despite the slower than expected worldwide economic recovery, demand is on the rise for the majority of the materials covered in this report.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

International Calendar . . . . . . . . . . . . . . . . . 7 Ceramics in the News . . . . . . . . . . . . . . . . . . 8 People in the News . . . . . . . . . . . . . . . . . . . 10

³The 2012 Materials Handbook CI’s exclusive annual reference source and purchasing guide details hundreds of raw and manufactured materials for the ceramic, glass, and related industries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Buyers’ Connection . . . . . . . . . . . . . . . . . 91 Services Marketplace . . . . . . . . . . . . . . . 93

SPECIAL SECTION | RESOURCE MANAGEMENT

Classified Advertisements . . . . . . . . . . 101

The Next Stage of Compliance Compliance with REACH regulation requires companies to have up-to-date information on chemical substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Advertiser Index . . . . . . . . . . . . . . . . . . . 102

ON THE COVER: Photo courtesy of H.C. Starck.

Safety in Technology Exoskeletal technologies support the musculoskeletal system while allowing full spatial and rotational freedom of motion . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

With a MobileTag go from Print to Web ³ Simply snap a photo of the mobile tag with your Smartphone, and you can conveniently go from a page in our magazine to a webpage. CERAMIC INDUSTRY (ISSN 0009-0220) is published 12 times annually, monthly, by BNP Media, 2401 W. Big Beaver Rd., Suite 700, Troy, MI 48084-3333. Telephone: (248) 362-3700, Fax: (248) 362-0317. No charge for subscriptions to qualified individuals. Annual rate for subscriptions to nonqualified individuals in the U.S.A.: $178.00 USD. Annual rate for subscriptions to nonqualified individuals in Canada: $216.00 USD (includes GST & postage); all other countries: $228.00 (Int’l mail) payable in U.S. funds. Printed in the U.S.A. Copyright 2012, by BNP Media. All rights reserved. The contents of this publication may not be reproduced in whole or in part without the consent of the publisher. The publisher is not responsible for product claims and representations. Periodicals Postage Paid at Troy, MI and at additional mailing offices. POSTMASTER: Send address changes to: CERAMIC INDUSTRY, P.O. Box 2145, Skokie, IL 60076. Canada Post: Publications Mail Agreement #40612608. GST account: 131263923. Send returns (Canada) to Pitney Bowes, P.O. Box 25542, London, ON, N6C 6B2. Change of address: Send old address label along with new address to CERAMIC INDUSTRY, P.O. Box 2145, Skokie, IL 60076. For single copies or back issues: contact Ann Kalb at (248) 244-6499 or [email protected].

CERAMIC INDUSTRY ³ January 2012

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®

³ INSIDECI by Susan Sutton | Editor-in-Chief, Integrated Media

www.ceramicindustry.com 6075 B Glick Road • Powell, OH 43065 281-550-5855 (p) For subscription information or service, please contact Customer Service at: 847-763-9534 (p) • 847-763-9538 (f) • [email protected]

Persistence I’m a huge fan of professional soccer, particularly the Barclay’s Premier League (BPL) in England. I follow a couple of Major League Soccer teams here in the U.S., but the amazing pace and skill of the players in the BPL makes those matches particularly exciting and fascinating to watch. The BPL season runs from August to May, and it’s around this time of year that the sheer persistence of the players is impressive. It’s mid-season, legs are tired, injuries are niggling, and it’s cold. Watching the players slog it out in the frigid and often snowy, wet conditions is truly inspiring. Even if the match isn’t going their way, it’s rare that any of these top-flight players actually give up—or even slow down. As Manchester United’s stalwart defender Rio Ferdinand has said on multiple occasions, “We never know when we’re beaten.” He’s not claiming ignorance; he means that the players work as hard as they can for the entire game, regardless of the numbers on the scoreboard. I would love to be able to say that we’re at least halfway through the economic downturn that has plagued most of the world since 2008. It seems like every time we see some good news, bad news follows right behind it. Indeed, the ongoing European debt crisis provides ups and downs on nearly a daily basis. What I can say—definitively—is that it’s truly an honor to be part of an industry that does not give up, despite harsh conditions and uncertain results. It’s inspiring to hear continued news of technology innovations, facility expansions and personnel development. And it’s exciting for all of us at Ceramic Industry to be able to share this great information with you. Here’s to a great 2012!

EDITORIAL / PRODUCTION STAFF Amy Vallance, Publisher 281-256-8492 (p) • 248-283-6543 (f) • [email protected] Susan Sutton, Editor-in-Chief, Integrated Media 330-336-4098 (p) • 248-502-2033 (f) • [email protected] Teresa McPherson, Managing Editor 734-332-0541 (p) • 248-502-2102 (f) • [email protected] Kelsey Seidler, Associate Editor 614-789-1881 (p) • 248-502-2051 (f) • [email protected] Mike Holmes, Art Director 412-306-4358 (p) • 248-502-1075 (f) • [email protected] Bryon T. Palmer, Production Manager 248-244-6435 (p) • 248-502-9113 (f) • [email protected] Ralph Ruark, Senior Technical Editor Charles Semler; Sandra Spence; Lynn Bragg; George Muha, Contributing Editors

SALES STAFF Patrick Connolly • Europe/Asia 44-1702-477341 (p) • 44-1702-477559 (f) • [email protected] Amy Vallance • Midwest, West and Southwest U.S., and Western Canada 281-256-8492 (p) • 248-283-6543 (f) • [email protected] Brandon Miller • Eastern U.S. and Canada, Latin America 610-436-4220, ext. 8513 (p) • 248-502-9065 (f) • [email protected] Peg Van Winkle, Reprint Sales 614-760-4222 (p) • 248-283-6530 (f) • [email protected] Christopher Wilson, BNP Custom Media Group 248-244-8264 (p) • [email protected] Single Copy Sales • Ann Kalb Phone: 248-244-6499 • Fax: 248-244-2925 [email protected]

LIST RENTAL Postal contact: Kevin Collopy, Senior Account Manager Phone: 845-731-2684 • Toll Free: 800-223-2194 x684 [email protected] Email contact: Michael Costantino, Senior Account Manager Phone: 845-731-2748 • Toll Free: 800-223-2194 x748 [email protected]

AUDIENCE DEVELOPMENT Kristine Wyatt • Audience Development Manager Kelly Carlson • Multimedia Specialist Catherine M. Ronan • Corporate Audience Audit Manager

DIGITAL EDITION EXCLUSIVE: Expanded Raw & Manufactured Materials 2012 Overview This month’s digital edition will include details for a number of additional materials, including magnesium compounds, manganese, niobium and tantalum, soda ash, and more!

ONLINE EXTRA: New Functionalities in Abundant Element Oxides A “ubiquitous element strategy” has been developed for overcoming potential deficiencies of rare elements.

ONLINE EXTRA: 2012 Chemical Industry Perspective Booz & Co. shares insights on the current business environment and future trends for chemical companies.

MATERIALS HANDBOOK The online version of the Materials Handbook at www. ceramicindustry.com/materialshandbook is searchable by product or company, and includes extras such as hotlinks, spec sheets, and videos for select suppliers.*

DIGITAL EDITION CI’s digital editions are easy to read, search and download. This month’s digital edition is sponsored by Mason Color Works.

*Supplier listings indicate paid advertising. Contact Darlene Dipzinski at [email protected] for pricing and additional details.

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January 2012 ³ WWW.CERAMICINDUSTRY.COM

EDITORIAL ADVISORY BOARD Surinder Maheshwary, Director, Quality Assurance/Process Improvement, Dal-Tile International; William Babik, Technical Sales Manager, Nabertherm Inc.; Charles Semler, Ph.D., Refractories Consultant, Semler Materials Services; Gary Childress, General Manager, Orton Ceramic Foundation; Matthew Centa, Technical Support Manager - Ceramics & Glass, Rio Tinto Minerals; James E. Houseman, Ph.D., President, Harrop Industries, Inc.

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BNP Media Helps People Succeed in Business with Superior Information



³INTERNATIONALCALENDAR

May 20-23 10th CMCEE International Symposium on Ceramic Materials and Components for Energy and Environmental Applications ³Dresden, Germany, www.cmcee12.de

Jan 22-27 International Conference and Exposition on Advanced Ceramics and Composites (ICACC ’12) ³Daytona Beach, Fla., www.ceramics.org

* May 22-25 ceramitec 2012 ³Munich, Germany, www.ceramitec.de

Jan 23-26 36th Annual Conference on Composites, Materials and Structures ³Cape Canaveral, Fla., http://advancedceramics.org

Think Fine and Finer ▲

* Feb 7-10 Cevisama 2012 ³Valencia, Spain, http://cevisama.feriavalencia.com

 May 15-17 CISILE 2012 ³Beijing, China, www.cisile.com.cn/en

DMQ-10

* Feb 21-23 Composites 2012 ³Las Vegas, Nev., www.acmanet.org

Small Media Milling Systems for submicron grinding and nanodispersions

HSA-1/1-S Combination dry grinding/wet grinding laboratory mill

Feb 21-23 American Craft Council Wholesale Show ³Baltimore, Md., www.craftcouncil.org/wholesale

▲

* March 11-15 Pittcon ³Orlando, Fla., www.pittcon.org * March 24-26 DECO ‘12 ³Las Vegas, Nev., www.sgcd.org * March 26-28 St. Louis Section 47th Annual Symposium ³St. Louis, Mo., www.ceramics.org March 27-29 Westec ³Los Angeles, Calif., www.westeconline.com April 17-20 Coverings ³Orlando, Fla., www.coverings.com  April 18-19 NanoManufacturing Conference & Exhibits ³ Boston, Mass., www.sme.org/ cgi-bin/get-event.pl?--002081000007-home--SME-

Union Process offers fine grinding and dispersing systems capable of delivering narrow, uniform particle size distributions in the micron, sub-micron and nanometer ranges. Varying materials of construction are available for grinding tank linings, shafts, agitator arms and disks for material compatibility or metal-free milling systems. • Lab, pilot scale or full-sized production equipment available for either wet or dry milling. • Union Process is a full service solution provider offering grinding and dispersing equipment, grinding media, lab testing and process optimization services, toll milling, particle size analyses and particle characterization.

We provide solutions for all of your grinding and dispersing needs.

Contact us today!

* May 8-10 Powder and Bulk Solids ³Chicago, Ill., www.powderbulksolids.com * Look for Ceramic Industry magazine at these events! For a more detailed listing, visit our website at www.ceramicindustry.com.

Phone (330) 929-3333 Fax (330) 929-3034 Email: [email protected] www.unionprocess.com © 2008, Union Process, Inc. All rights reserved. 508-23

Expanding the Possibilities For Size Reduction CI07084UnionP.indd 1

6/11/08 2012 3:31:42 7 PM CERAMIC INDUSTRY ³ January

³ INTHENEWS Asahi Glass to Be Installed in Subaru Impreza American Securities Completes Unifrax Acquisition American Securities LLC recently announced that, in partnership with company management, it has completed its acquisition of Unifrax I LLC. American Securities previously invested in Unifrax in 2003 and successfully exited its partnership with management in 2006. “We have remained friends with Unifrax’s management team since we exited our original investment,” said Marc Saiontz, a managing director of American Securities. “There continues to be a growing need for energy efficiency, as well as increasingly tighter emission regulations and stricter fire protection requirements throughout the world. We believe Unifrax is well-positioned to benefit from these global trends and is poised for continued growth. Unifrax was in 2003 and remains today exactly the type of business American Securities likes to invest in—a market leader in a stable demand industry with outstanding growth prospects and a strong management team led by David Brooks.” “We are very enthusiastic about the future of our business,” said David E. Brooks, president and CEO. “Re-establishing our relationship with American Securities is another positive step in the continued implementation of Unifrax’s long-term growth strategy. We are excited about working together again as we continue to expand our business.” For further details, visit www.unifrax.com.

O

Don’t let abrasive materials wear you down Lined with thick ceramic and tungsten carbide coatings, our abrasion-resistant ceramic feeder is designed to handle the most abrasive materials. Its robust construction offers indisputable long life and proven reliability. Find out more at www.flsmidth.com

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January 2012 ³ WWW.CERAMICINDUSTRY.COM

Asahi Glass Co. Ltd. (AGC) recently announced that its UV Verre Premium™ is to be installed in Fuji Heavy Industries’ Subaru Impreza as an option. The glass is reportedly the world’s first tempered glass for automotive front door windows that filters out approximately 99% of the sun’s ultraviolet (UV) rays. Fuji Heavy Industries has made a full model change of the car, aiming to achieve a stylish exterior and luxurious interior. In developing this vehicle line, the company considered drivers’ lifestyles and values, and adopted UV Verre Premium as an option in response to consumers’ concerns about UV protection. The glass reportedly filters out the sun’s UV rays completely to help to make the drivers more comfortable. For more information, visit www.agc.com.

Morgan Technical Ceramics Announces High-Volume Piezoelectric Production Morgan Technical Ceramics (MTC) recently announced that its ElectroCeramics manufacturing site in Bedford, Ohio, can design and manufacture a comprehensive range of precision piezoelectric ceramic components made of lead zirconate titanate (PZT) for use in aerospace, medical, industrial, commercial, and consumer sensor and actuator applications. The company can produce intricate piezoelectric designs that meet demanding specifications for such products as transducers, sensors, actuators and bimorphs. The manufacturing capability reportedly allows MTC to produce high volumes of complex and unique shapes with precise geometries that other technologies and processing techniques cannot achieve. This is particularly relevant for markets such as computer memory storage, which requires that the PZT element be made in volumes of millions per week with dimensional tolerances of ± 50 microns, electrical tolerances of ± 15% and frequency tolerances of ± 5% on a part that is miniature in size. Visit www.morgantechnicalceramics.com for details.

Riedhammer to Supply Foam Glass Production Lines to Norwegian Manufacturer Riedhammer announced it will supply two new foam glass production lines to Norwegian company Norsk Glassgjen-

vinning. The installation includes a foam glass production plant consisting of two fast-firing tunnel kilns with belt conveyance, as well as the associated mixing and dosing technology for the production of foam glass gravel. Plant production is planned to begin in the first quarter. The Riedhammer technology reportedly enables a maximum degree of production automation with low investment costs. The kilns are designed to minimize energy losses and to make the best possible use of waste heat for further process steps in order to obtain excellent specific energy consumption levels. Visit www.sacmi.com for more information.

Energy Technology (INET) at Tsinghua University for testing and training. China is reportedly focused on creating its independence in energy generation through scientific and technological advancements, in a safe and environmentally friendly manner. The country

has been described as developing into a leading center for new nuclear reactor designs. With its inherent safety features, the HTR with pebble bed modules is considered to be a promising nextgeneration reactor. Visit www.schott.com for more information. 

SAINT GOBAINLO MASS ‡ SYSTEMS ¨

Ceradyne Subsidiary Licenses Patents to Nissin Ion Equipment Ceradyne Inc. announced that its SemEquip Inc. subsidiary has licensed its technology (including applicable patents) related to its cluster ion implant hardware to Nissin Ion Equipment Co. Ltd. of Kyoto, Japan. In addition, Nissin Ion Equipment USA Inc. has purchased certain assets and assumed related SemEquip obligations, including facility leases. Nissin announced it intends to hire many former SemEquip employees to continue the development, manufacturing and marketing of the ion implant hardware. SemEquip will continue to market its cluster ion chemistry, particularly boron cluster ions such as B18H22, to the semiconductor industry. SemEquip has been working with Nissin for over 10 years on this technology and associated semiconductor ion implant equipment. For more details, visit www.ceradyne.com.

SCHOTT Supplies Technology for High-Temperature Reactor China’s first commercial high-temperature reactor (HTR) in the province of Shandong will reportedly be one of the most modern nuclear power plants in the world. SCHOTT has been selected to supply its hermetic glass-to-metal sealed electrical penetration assemblies (EPAs). The first feedthrough has been delivered to the Institute of Nuclear and New

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CERAMIC INDUSTRY ³ January 2012

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³ PEOPLEINTHENEWS Dan Egbert has been appointed parts sales associate for Stedman. He will be responsible for customer support of all crusher parts and spares. Egbert has over 19 years of experience at Stedman, starting in the Shipping and Receiving department. He also has experience in Unit Assembly and Installation and Service. He most recently served as Production clerk, a position that gave him knowledge of crusher construction, operations and parts.

American Chemet’s Skip Klatt Passes Away Skip Klatt, longtime vice president of Sales at American Chemet, passed away November 21, 2011, after an 18-month battle with lymphoma and leukemia. Klatt was an owner of American Chemet and served on its board and committees for more than 30 years. His vision and enthusiasm for the company helped to lead its successful growth and diversification efforts during the past two decades. An avid fisherman, Klatt also volunteered with the Boy Scouts; he was a Silver Beaver and Order of the Arrow recipient. Donations can be made in his honor to the NE Illinois Counsel, Boy Scouts of America, 2745 Skokie Valley Rd., Highland Park, IL 60035; or to the Leukemia and Lymphoma Society Donor Services, P.O. Box 4072, Pittsfield, MA 01202. American Chemet’s website is located at www.chemet.com.

Brian Hartwig has been promoted to chief operating officer for Schenck AccuRate Inc. Hartwig will work with Dirk Maroske, president and CEO, to set the company objectives and fulfill

the responsibilities of managing the company’s day-to-day operations. Hartwig has been operating as an interim second officer of the company since the end of February. In the four

years he has been with Schenck AccuRate, his responsibilities have included R&D Engineering manager, director of Engineering, and director of After-Sales Business. 

Better Characterization of Advanced Ceramic Materials

r d Semina n e k e e W – Ceramics FL Focus on na Beach, to y a D – n Hilto 2, 2012 Jan. 21–2 012 – ICACC 2 rS e C A Prior to

Register now! Special Weekend Seminar – Understanding Thermal Analysis & Thermophysical Properties of Advanced Ceramics

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January 2012 ³ WWW.CERAMICINDUSTRY.COM

NETZSCH Instruments North America, LLC Headquarters 129 Middlesex Turnpike BURLINGTON, MA 01803, USA Tel.: +1 781 272 5353 [email protected]

Crystalline boron. Photo courtesy of H.C. Starck.

³ Despite the slower than expected worldwide economic recovery, demand is on the rise for the majority of the raw and manufactured materials covered in this report. compiled by Susan Sutton, Editor-in-Chief, Integrated Media

Manufactured Abrasives Imports and higher operating costs continued to challenge abrasives producers in the U.S. and Canada in 2010. Foreign competition, particularly from China, is expected to persist and further curtail production in North America. Abrasives markets are greatly influenced by activity in the manufacturing sector in the U.S. During 2009, downturns in the U.S. manufacturing sector caused modest decreases in U.S. manufactured abrasives production, but significant decreases in consumption. This was particularly true of manufacturing activities in the aerospace, automotive, furniture, housing and steel industries. The U.S. abrasive markets also are influenced by economic and technological trends. As the world and the U.S. slowly began to recover from the global economic recession during 2010, U.S. manufactured abrasives production and consumption also slowly began to show signs of improvement. Production of regular-grade fused aluminum oxide had an estimated value of $1.92 million in 2010 (U.S. and Canada),

remaining flat at 10,000 t. U.S. imports for consumption shot up by 164.8% to 170,000 t, while exports increased by 54.5% to 19,000 t. U.S. and Canadian production of crude silicon carbide was also flat in 2010 (at 35,000 t) and had an estimated value of $26.4 million in 2010. U.S. imports for consumption increased by 79.5% to 140,000 t, while exports increased by 15.9% to 24,000 t. Apparent domestic consumption of silicon carbide increased by 62.5% in 2010, to 150,000 t.

Bauxite and Alumina According to Global Industry Analysts, Inc., the global market for bauxite is forecast to reach 191.7 Mt by 2015, while the global market for alumina is expected to reach 70.3 Mt. Refractories and abrasives represent the major markets for non-metallurgical bauxite and alumina. Other applications include aluminous cements, chemicals and proppants. High-performance materials will influence future demand for both bauxite and alumina. The application of alumina trihydrate in flame retardants and calcined alumina in electronic ceramics

and bioceramics is expected to grow significantly in the coming years.1 Based on production data from the International Aluminum Institute and industry sources in China, world alumina production in 2010 was up by 14% over 2009 levels. Increases in production from reopened, new and expanded mines in Australia, Brazil, Guinea, India, and Jamaica accounted for most of the 6% increase of worldwide production of bauxite in 2010 vs. 2009 levels. U.S. imports of bauxite for consumption increased by 16.5% to 9.1 Mt in 2010, while exports jumped by 87% to 43,000 t. Alumina imports decreased by 10.2% to 1.7 Mt, while exports were up 79.7% to 1.7 Mt.

Boron Minerals The estimated distribution pattern for boron compounds consumed in the U.S. in 2010 was: glass and ceramics, 78%; soaps, detergents and bleaches, 4%; agriculture, 4%; enamels and glazes, 3%; and other, 11%. While the global economic downturn negatively affected sectors vital for boron consumption, such as the construction and automotive industries, the moderate economic recovery in 2010 created steady growth in boron production and consumption. Demand for fiber glass, the principle use of boron, is expected to increase 2.3% annually through 2012. Consumption of boron used in high-tech fiber glass sectors, such as electronic products and wind turbines, is expected to increase by 10% in North America and 13% in Europe by 2012. Demand for borates is expected to shift slightly away from detergents and soaps toward glass and ceramics.

Clays In 2010, clay and shale production was reported in 39 U.S. states. Apparent consumption increased by 9.5% to reach 23 Mt. Sales or use was estimated to be 27 Mt valued at $1.5 billion. Major uses for specific clays were estimated as follows: • ball clay—floor and wall tile, 36%; sanitaryware, 22%; and other uses, 42% CERAMIC INDUSTRY ³ January 2012

11

RAW & MANUFACTURED MATERIALS

• bentonite—absorbents, 25%; drilling mud, 19%; foundry sand bond, 17%; iron ore pelletizing, 12%; and other uses, 27% • common clay—brick, 50%; lightweight aggregate, 25%; cement, 16%; and other uses, 9% • fire clay—heavy clay products, 38%; and refractory products and other uses, 62% • fuller’s earth—absorbent uses, 74%; and other uses, 26% • kaolin—paper, 58%; and other uses, 42% Many markets for clays improved in 2010 as the U.S. economy began to recover from the recession. A slight improvement in commercial and private housing construction resulted in increased sales of ball clay and common clay. Bentonite sales increased with greater demand from the oil drilling, foundry and iron ore industries. Kaolin production improved because of a slight recovery in world paper markets and greater construction activity. Fuller’s earth and kaolin sales increased mainly on the strength of increased exports.

Feldspar According to Merchant Research & Consulting Ltd., the global demand for feldspar in its end-use markets is increasing, particularly in Asia, Latin America and the Middle East. Consumption is expected to increase 3% annually in the Asia-Pacific region, while Europe will offer high growth rates of feldspar consumption for the ceramic industry. Challenges to the worldwide feldspar industry include increasing transportation costs and rising natural gas and fuel oil prices. In addition, demand from the glass industry is projected to decline over the next five years.2 In the U.S., feldspar production was valued at around $36 million in 2010. Estimated marketable production increased by 3.6% to 570,000 t, while imports for consumption remained flat at 2,000 t. Exports jumped 62.5% to 13,000 t. Apparent consumption was estimated at 560,000 t, a 2.9% increase over 2009. 12

High-purity, semi-friable, medium-density, virgin green silicon carbide. Photo courtesy of Washington Mills.

Glass represented 70% of the end-use distribution, while pottery and other uses made up the remaining 30%. Most feldspar consumed by the glass industry is for the manufacture of container glass. The glass container industry was moderately stable, although competing materials in some market segments (e.g., baby food, fruit juices, mineral water and wine), along with a recent trend to import less expensive containers from China, presented challenges. Feldspar use in tile and sanitaryware continued to be sluggish because of the struggling housing market. At the request of European ceramic makers, the European Union (EU) began an antidumping probe of imported ceramic tile from China to determine whether Chinese imports had caused injury to the EU’s industry. Antidumping duties could be assessed against Chinese imports in the EU, depending on the results of the investigation.

Kyanite and Related Materials One firm in Virginia with integrated mining and processing operations produced kyanite from hard-rock open pit mines in 2010, while another company produced synthetic mullite in Georgia. Commercially produced mullite is synthetic, produced from sintering or fusing feedstock materials such as kyanite or bauxitic kaolin; natural mullite occurrences are typically rare and uneconomic to mine. Of the kyanite-mullite output, 90% was estimated to have been used in refractories and 10% in other uses. Of the refractory usage, an estimated 60-65%

January 2012 ³ WWW.CERAMICINDUSTRY.COM

was used in ironmaking and steelmaking, and the remainder in the manufacture of chemicals, glass, nonferrous metals, and other materials. U.S. mine production of kyanite and related materials decreased by 1.4% in 2010, to 70,000 t. Synthetic mullite production remained flat at 40,000 t. Apparent consumption of kyanite and related materials also decreased, by 5.6% to 85,000 t, while exports jumped 23.1% to 32,000 t.

Rare Earths Roskill Information Services reports that China is estimated to account for 94% of the world’s supply of rare earths in 2011, with most of the remainder coming from Russia and the U.S. By 2015, the rest of the world will account for just over a quarter of world supply; this proportion is likely to increase through 2020. Global demand for rare earths grew 5% per year between 2005-2010 (though the market shrank in 2009), according to Roskill. Growth in demand in China was much higher, running at 11% per year. The country now accounts for 70% of world demand, which is estimated at 125,000 t in 2010. Consumption of rare earths in the rest of the world declined by nearly 4% per year during the same period. The decline was partly due to the impact of the recession, but also reflected the increasing volume of downstream processing within China and the tightening export quota. According to The Freedonia Group, Inc., world demand for rare earths is forecast to expand 7.1% per year to 180,000 t by 2015 (see Table 1). In dollar terms, sales are expected to more than triple, from $3 billion in 2010 to $9.2 billion in 2015. Neodymium and dysprosium are expected to post the fastest growth rates of any rare earth types, spurred by increased sales of heatresistant NdFeB permanent magnets. However, cerium will remain the most widely used rare earth, accounting for almost one-third of the 2015 tonnage total.8 The estimated value of refined rare earths imported by the U.S. in 2010

Table 1. World rare earth demand (metric tons). Region

2010

2015

% Annual Growth

North America

12,800

17,000

5.8

Western Europe

10,300

13,700

5.9

Asia-Pacific

99,600

143,000

7.5

Central and South America

1,150

1,405

4.1

Eastern Europe

2,600

2,990

2.8

Africa/Mideast

1,550

1,905

4.2

128,000

180,000

7.1

Total Source: The Freedonia Group, Inc.

was $161 million, an increase from $113 million imported in 2009. Based on reported data through July 2009, the estimated 2009 distribution of rare earths by end use, in decreasing order, was: chemical catalysts, 22%; metallurgical applications and alloys, 21%; petroleum refining catalysts, 14%; automotive catalytic converters, 13%; glass polishing and ceramics, 9%; rare earth phosphors for computer monitors, lighting, radar, televisions, and X-ray intensifying film, 8%; permanent magnets, 7%; electronics, 3%; and other, 3%.

Silica Industrial sand and gravel (often called silica, silica sand and quartz sand) valued at about $777 million was produced by 68 companies from 124 operations in 34 states in 2010. Leading states (in order of tonnage produced) were Illinois, Wisconsin, Texas, Oklahoma, Louisiana, Minnesota, Michigan and California. Combined production from these states represented 59% of the domestic total. Total U.S. production in 2010 increased by 60% to 26.5 Mt. About 31% of the U.S. tonnage was used as glassmaking sand, 25% as hydraulic fracturing sand and wellpacking and cementing sand, 13% as foundry sand, 8% as whole-grain silica, 7% as whole-grain fillers and building products, 4% as golf course sand, 3% as ground and unground silica for chemical applications, and 9% for other uses. Apparent consumption increased slightly (4.3%) to 24 Mt in 2010.

Exports rose to 2.6 Mt (up 20.9%), while imports for consumption increased by 15.8% to 110,000 t. Imports of silica are generally of two types—small shipments of very high-purity silica or a few large shipments of lower grade silica shipped only under special circumstances (e.g., very low freight rates).

Zirconium U.S. imports of zirconium ores and concentrates (zirconia content) increased by 23.8% in 2010, to 11,600 t, while imports of zirconia (ZrO2) dropped by 15.7% to 2,370 t. However, exports of zirconium ores and concentrates increased by 32.3% to 34,000 t, and zirconia exports jumped by 100.3% to 6,110 t. Global consumption of zirconium silicate (zircon) rebounded strongly in 2010, reaching 1.33 Mt, according to Roskill Information Services. Growth over the last decade has come mainly from the ceramic and chemical sectors, growing by 4.1% and 7.5% per year, respectively, compared to overall market growth of 2.6% per year. China now accounts for over half of total consumption, with the wider Asian region accounting for two-thirds of consumption. Other major ceramic-producing countries, such as Spain and Italy, are also large consumers of zircon. Growth in zircon production has lagged consumption since the early 2000s, but an almost doubling in zircon prices during 2004-2006 put more emphasis on primary zircon production. (Zircon has historically been a byproduct of titanium mineral extrac-

Table 2. World zirconium mine production (thousand metric tons). Country

2009

Australia

476

481

1.1

Brazil

18

18

0.0

China

130

140

7.7

India

31

31

0.0

Indonesia

63

60

-4.8

South Africa

392

390

-0.5

Ukraine

35

35

0.0

U.S.

W

W

W

Other

19

30

57.9

1,160

1,190

2.6

World total (rounded)

2010* % Change

*estimated W = withheld Source: www.usgs.gov

tion, and output has long been constrained by titanium mineral demand.) New deposits entering production (e.g., Victoria and South Australia) are being mined primarily for their zircon content. Table 2 details worldwide zirconium mine production. Future demand for zircon is forecast to increase by 5.4% per year, led by ceramics and chemical output in China. Recovery in demand from Western markets is likely to be protracted, particularly in the ceramic sector. Other end uses are forecast to show little growth and could be negatively affected by higher prices and substitution.12  Editor’s note: The foregoing information, except where noted, was compiled from the U.S. Geological Survey (www.usgs.gov). Reference details are included with this article online at www.ceramicindustry.com. All units are in metric tons except where otherwise noted. In most cases, 2010 data were the latest available. For additional details regarding the uses of these materials in the ceramic, glass and related industries, visit the Materials Handbook pages in this issue. DIGITAL EDITION EXCLUSIVE Read this article in our Digital Edition for extended details on many of the materials included here, as well as additional coverage on materials such as magnesium compounds, manganese, niobium and tantalum, soda ash, and more!

CERAMIC INDUSTRY ³ January 2012

13

Crystalline boron. Photo courtesy of H.C. Starck.

Raw & Manufactured

³ Despite the slower than expected worldwide economic recovery, demand is on the rise for the majority of the raw and manufactured materials covered in this report. compiled by Susan Sutton, Editor-in-Chief, Integrated Media

Manufactured Abrasives Imports and higher operating costs continued to challenge abrasives producers in the U.S. and Canada in 2010. Foreign competition, particularly from China, is expected to persist and further curtail production in North America. Abrasives markets are greatly influenced by activity in the manufacturing sector in the U.S. During 2009, downturns in the U.S. manufacturing sector caused modest decreases in U.S. manufactured abrasives production, but significant decreases in consumption. This was particularly true of manufacturing activities in the aerospace, automotive, furniture, housing and steel industries. S1

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The U.S. abrasive markets also are influenced by economic and technological trends. As the world and the U.S. slowly began to recover from the global economic recession during 2010, U.S. manufactured abrasives production and consumption also slowly began to show signs of improvement. Production of regular-grade fused aluminum oxide had an estimated value of $1.92 million in 2010 (U.S. and Canada), remaining flat at 10,000 t. U.S. imports for consumption shot up by 164.8% to 170,000 t, while exports increased by 54.5% to 19,000 t. U.S. and Canadian production of crude silicon carbide was also flat in 2010 (at 35,000 t) and had an estimated value of $26.4 million in 2010. U.S. imports for consumption increased

Digital Exclusive | Special Section

by 79.5% to 140,000 t, while exports increased by 15.9% to 24,000 t. Apparent domestic consumption of silicon carbide increased by 62.5% in 2010, to 150,000 t. Global prices of abrasive aluminum oxide and silicon carbide, which had leveled out or dropped during the first three quarters of 2009, began moving steadily higher in the last quarter of 2009. This price trend continued through 2010.

Bauxite and Alumina According to Global Industry Analysts, Inc., the global market for bauxite is forecast to reach 191.7 Mt by 2015, while the global market for alumina is expected to reach 70.3 Mt. Refractories and abrasives represent the major markets for nonmetallurgical bauxite and alumina. Other applications include aluminous cements, chemicals and proppants. High-performance materials will influence future demand for both bauxite and alumina. The application of alumina trihydrate in flame retardants and calcined alumina in electronic ceramics and bioceramics is expected to grow significantly in the coming years.1 Based on production data from the International Aluminum Institute and industry sources in China, world alumina production in 2010 was up by 14% over 2009 levels. Increases in production from reopened, new and expanded mines in Australia, Brazil, Guinea, India, and Jamaica accounted for most of the 6% increase of worldwide production of bauxite in 2010 vs. 2009 levels (see Table 1). U.S. imports of bauxite for consumption increased by 16.5% to 9.1 Mt in 2010, while exports jumped by 87% to 43,000 t. Alumina imports decreased by 10.2% to 1.7 Mt, while exports were up 79.7% to 1.7 Mt. Apparent U.S. consumption (both bauxite and alumina) decreased by 17.5% in 2010, to 2.1 Mt.

High-purity, semi-friable, medium-density, virgin green silicon carbide. Photo courtesy of Washington Mills.

the moderate economic recovery in 2010 created steady growth in boron production and consumption. Demand for fiber glass, the principle use of boron, is expected to increase

culture, 4%; enamels and glazes, 3%; and other, 11%. While the global economic downturn negatively affected sectors vital for boron consumption, such as the construction and automotive industries,

Table 1. World bauxite mine production (thousand metric dry tons). Country

2009

2010*

% Change

Australia

65,200

70,000

7.4

Brazil

28,200

32,100

13.8

China

40,000

40,000

0.0

Greece

2,100

2,000

-4.8

Guinea

15,600

17,400

11.5

Guyana

1,760

1,800

2.3

India

16,000

18,000

12.5

Jamaica

7,820

9,200

17.6

Kazakhstan

5,130

5,300

3.3

Russia

5,780

4,700

-18.7

Suriname

4,000

3,100

-22.5

NA

NA

NA

2,500

2,500

0.0

U.S. Venezuela

Boron Minerals

Vietnam

The estimated distribution pattern for boron compounds consumed in the U.S. in 2010 was: glass and ceramics, 78%; soaps, detergents and bleaches, 4%; agri-

Other countries World total (rounded)

30

30

0.0

4,740

4,440

-6.3

199,000

211,000

6.0

*estimate NA = not available Source: www.usgs.gov

CERAMIC INDUSTRY ³ January 2012

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DIGITAL EXCLUSIVE SPECIAL SECTION Table 2. U.S. clay mine production (thousand metric tons). Type

2009

2010*

% Change

Ball clay

831

910

9.5

Bentonite

3,650

4,000

9.6

Common clay

12,500 13,500

8.0

Fire clay

320

270

-15.6

Fuller’s earth

2,010

2,300

14.4

Kaolin

5,290

5,700

7.8

*estimate Source: www.usgs.gov

Ball clays and kaolins. Photo courtesy of Unimin Corp.

2.3% annually through 2012. Consumption of boron used in high-tech fiber glass sectors, such as electronic products and wind turbines, is expected to increase by 10% in North America and 13% in Europe by 2012. Demand for borates is expected to shift slightly away from detergents and soaps toward glass and ceramics. Although borate consumption in China decreased in 2009 due to the economic downturn, consumption is projected to increase due to demand from the country’s domestic ceramic and glass industries. With low-grade domestic boron reserves and the anticipated rise in demand, Chinese imports from Chile, Russia, Turkey, and the U.S. are expected to increase over the next several years. Europe and emerging markets are requiring more stringent building standards with respect to heat conservation, which directly correlates to higher consumption of borates for insulation fiber glass. U.S. boric acid exports increased by 46.2% in 2010, to 250,000 t, while exports of refined sodium borates increased by 55.9% to 650,000 t. U.S. imports for consumption of borax decreased from 1,000 t to less than half that amount in 2010, while other imports increased as follows: boric acid, up 8.3% (to 39,000 t); colemanite, up 12.9% (to 35,000 t); and ulexite, up 7.1% (to 30,000 t). S3

Clays In 2010, clay and shale production was reported in 39 U.S. states (see Table 2). Apparent consumption increased by 9.5% to reach 23 Mt. Sales or use was estimated to be 27 Mt valued at $1.5 billion. Major uses for specific clays were estimated as follows: • ball clay—floor and wall tile, 36%; sanitaryware, 22%; and other uses, 42% • bentonite—absorbents, 25%; drilling mud, 19%; foundry sand bond, 17%; iron ore pelletizing, 12%; and other uses, 27% • common clay—brick, 50%; lightweight aggregate, 25%; cement, 16%; and other uses, 9% • fire clay—heavy clay products, 38%; and refractory products and other uses, 62% • fuller’s earth—absorbent uses, 74%; and other uses, 26% • kaolin—paper, 58%; and other uses, 42% Many markets for clays improved in 2010 as the U.S. economy began to recover from the recession. A slight improvement in commercial and private housing construction resulted in increased sales of ball clay and common clay. Bentonite sales increased with greater demand from the oil drilling, foundry and iron ore industries. Kaolin

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production improved because of a slight recovery in world paper markets and greater construction activity. Fuller’s earth and kaolin sales increased mainly on the strength of increased exports. U.S. exports increased by 22.7% to 4.7 Mt and included: ball clay, 17.1% to 41,000 t; bentonite, 35.2% to 960,000 t; fire clay (data includes some refractory-grade kaolin), 20.4% to 395,000 t; fuller’s earth, 266.7% to 330,000 t; and kaolin, 13.5% to 2.6 Mt. Exports of clays not elsewhere classified were down 2.4% to 365,000 t.

Feldspar According to Merchant Research & Consulting Ltd., the global demand for feldspar in its end-use markets is increasing, particularly in Asia, Latin America and the Middle East. Consumption is expected to increase 3% annually in the Asia-Pacific region, while Europe will offer high growth rates of feldspar consumption for the ceramic industry. Challenges to the worldwide feldspar industry include increasing transportation costs and rising natural gas and fuel oil prices. In addition, demand from the glass industry is projected to decline over the next five years.2 In the U.S., feldspar production was valued at around $36 million in 2010. Estimated marketable production increased by 3.6% to 570,000 t, while imports for consumption remained flat at 2,000 t. Exports jumped 62.5% to 13,000 t. Apparent consumption was estimated at 560,000 t, a 2.9% increase over 2009.

Glass represented 70% of the end-use distribution, while pottery and other uses made up the remaining 30%. Most feldspar consumed by the glass industry is for the manufacture of container glass. The glass container industry was moderately stable, although competing materials in some market segments (e.g., baby food, fruit juices, mineral water and wine), along with a recent trend to import less expensive containers from China, presented challenges. Because of environmental initiatives, fiber glass consumption for thermal insulation was forecast to expand steadily in the U.S. through 2013. Domestic feldspar consumption has been shifting from ceramics toward glass markets. Another growing segment in the glass industry is solar glass. While only about 5% of glass manufactured in Europe was used to produce solar glass in 2010, that market is expected to increase as the solar cell market develops, potentially surpassing consumption in the automotive sector in Europe by 2025. Feldspar use in tile and sanitaryware continued to be sluggish because of the struggling housing market. At the request of European ceramic makers, the European Union (EU) began an antidumping probe of imported ceramic tile from China to determine whether Chinese imports had caused injury to the EU’s industry. Antidumping duties could be assessed against Chinese imports in the EU, depending on the results of the investigation.

Graphite Although natural graphite was not produced in the U.S. in 2010, approximately 90 U.S. firms (primarily in the Northeastern and Great Lakes regions) used it for a variety of applications. The major uses of natural graphite in 2010 were estimated to be foundry operations and steelmaking, 32%; refractory applications and crucibles, 31%; brake linings, 8%; lubricants, 3%; and other applications, 26%. During the second half of 2009, worldw ide demand for g r aphite

began a slow increase, which continued steadily throughout 2010. Principal import sources of natural graphite included China, Mexico, Canada, Brazil and Madagascar (in descending order of tonnage). Combined, these sources accounted for 98% of the tonnage and 90% of the value of total imports. Mexico provided all the amorphous graphite, and Sri Lanka provided all the lump and chippy dust variety. China and Canada were, in descending order of tonnage, the major suppliers of crystalline flake and flake dust graphite. During 2010, China produced the majority of the world’s graphite, and China’s graphite production is expected to continue growing. In recent years, Canada has opened a number of new graphite mines; this trend is expected to continue through the next few years. According to Merchant Research & Con-

sulting Ltd., India is expected to become a competitive graphite market player due to technology advancements and the country’s increased capabilities for the production of good-quality, costeffective graphite.3 Apparent U.S. consumption of graphite in 2010 jumped 109% from the previous year, to 46,000 t. Imports for consumption increased to 51,000 t (up 54.5%), while exports declined by 45.5% to 6,000 t.

Kyanite and Related Materials One firm in Virginia with integrated mining and processing operations produced kyanite from hard-rock open pit mines in 2010, while another company produced synthetic mullite in Georgia. Commercially produced mullite is synthetic, produced from sintering or fusing feedstock materials such as kyanite CERAMIC INDUSTRY ³ January 2012

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DIGITAL EXCLUSIVE SPECIAL SECTION Table 3. World mine production of kyanite and related materials (thousand metric tons). Country

2009

2010* % Change

France

65

65

0.0

India

24

24

0.0

South Africa

210

265

26.2

U.S.

71

70

-1.4

Other countries

6

8

33.3

375

430

14.7

World total (rounded)

*estimate Source: www.usgs.gov

or bauxitic kaolin; natural mullite occurrences are typically rare and uneconomic to mine. Of the kyanite-mullite output, 90% was estimated to have been used in refractories and 10% in other uses. Of the

with that of the same period in 2009—in China, the leading producer, by about 15%; in Japan (second) by 38%; and in Russia (fourth) by 15%. Total world production increased by 22% during the same period. Of the total world refractories market, estimated to be approximately 23 Mt, crude steel manufacturing consumed around 70% of production. Global demand for refractory products grew significantly in the fourth quarter of 2009 and during 2010 as a result of the recovery of steel production and sharp reductions of refractory inventory implemented in 2009 across the supply chain. With the steel recovery continuing, mullite received increasing interest, as many refractory customers sought alternative aluminosilicate refractory minerals to refractory bauxite. Industry sources in the U.S., Europe, and Southeast Asia expressed concern

Industry sources in the U.S., Europe, and Southeast Asia expressed concern regarding the supply of 60% Al2O3 mullite grades from the U.S. refractory usage, an estimated 60-65% was used in ironmaking and steelmaking, and the remainder in the manufacture of chemicals, glass, nonferrous metals, and other materials. Steel production in the U.S. (ranked third in the world) rebounded in the first eight months of 2010, with an increase of 56% compared with the same period in 2009. (In the same period of 2009, steel production had declined by 49% vs. the first eight months of 2008.) Potentially increasing the demand for kyanitemullite, crude steel production in the other three of the world’s four leading steel-producing countries also increased in the first eight months of 2010 compared S5

regarding the supply of 60% Al2O3 mullite grades from the U.S. Such a potential shortage, along with the drive to reduce costs, resulted in a renewed interest in 60- and 70-grade mullite from China, although Chinese mullite prices were on the rise and the future availability there was uncertain. Because of increased demand, one company restarted all its kilns in Andersonville, Ga., in late 2009 and brought a new kiln onstream in early 2010, adding 75,000 tons annually to the company’s existing production capacity. U.S. mine production of kyanite and related materials decreased by 1.4% in 2010, to 70,000 t (see Table 3). Synthetic mullite production remained flat at

January 2012 ³ WWW.CERAMICINDUSTRY.COM

40,000 t. Apparent consumption of kyanite and related materials also decreased, by 5.6% to 85,000 t, while exports jumped 23.1% to 32,000 t.

Magnesium Compounds Seawater and natural brines accounted for about 54% of U.S. magnesium compounds production in 2010. Magnesium oxide and other compounds were recovered from seawater by three companies in California, Delaware, and Florida; from well brines by one company in Michigan; and from lake brines by two companies in Utah. Magnesite was mined by one company in Nevada, and olivine was mined by two companies in North Carolina and Washington. About 60% of the magnesium compounds consumed in the U.S. was used in agricultural, chemical, construction, environmental and industrial applications. The remaining 40% was used for refractories. Increased steel production and capacity utilization led to increased imports of dead-burned magnesia, compared with those in 2009. By July, dead-burned magnesia imports were almost 200,000 tons (gross weight), which was more than those for the full year in 2009. U.S. production of magnesium compounds in 2010 increased slightly (1.7%) to 243,000 t. Imports for consumption jumped by 70.5% to 295,000 t, while exports rose by 23.1% to reach 16,000 t. Apparent consumption increased by 30.8% in 2010, to reach 522,000 t. In August, the U.S. Department of Commerce’s International Trade Administration (ITA) published its final determinations on its investigation of magnesia-carbon brick dumping from China and Mexico into the U.S. The ITA established a dumping margin of 128.10% ad valorem for 14 producing/exporting companies in China and 236% ad valorem as the Chinawide rate. For Mexico, the ITA determined a dumping margin of 57.90% ad valorem. The ITA also found that subsidies existed for magnesia-carbon bricks exported from China, so it established countervailing duties of 24.24% ad

valorem for most companies exporting from China, with one firm having a rate of 253.87% ad valorem. In Australia, the country’s leading magnesia producer returned to full production capacity in June after running at about 25% of capacity since the beginning of 2009. The company also completed an expansion that increased its capacity by about 50% to bring the total to 175,000 t per year of caustic-calcined magnesia, 135,000 t per year of deadburned magnesia, and 35,000 t per year of fused magnesia. Another firm received government approval to develop its magnesite property in Tasmania and, in the fourth quarter, began drilling to delineate the magnesite resource. In Spain, the leading magnesite producer planned to open two new mines in 2011 with about 57 Mt of magnesite reserves to replace the company’s operating mines that, at present mining rates, have a remaining life of seven to eight years. In May 2010, a company in Turkey began production from a new 6,500 t/year fused magnesia furnace, which doubled its fused magnesia production capacity. In India, a new joint venture planned to develop the Panthal magnesite deposit and build a 30,000 t/ year dead-burned magnesia plant at the site by 2012. The world’s second-ranked olivine producer planned to close its 1.1 Mt/year mine in Greenland by the end of 2010. The company cited lower olivine prices and unfavorable market conditions as reasons for the closure. The mine had only been operating since 2005.

Manganese Manganese ore was consumed in the U.S. mainly by eight firms with plants principally in the East and Midwest in 2010. Most ore consumption was related to steel production, while additional quantities of ore were used for such nonmetallurgical purposes as production of dry cell batteries, in plant fertilizers and animal feed, and as a brick colorant. The global economic recovery coincided with the growth in the manganese

Bubbles can be formed from molten alumina, resulting in hollow spheres of low bulk density. Photo courtesy of Washington Mills.

market during 2010. Imports of manganese materials were significantly higher in 2010 than in 2009—82%, 104%, and 139% for manganese ore, ferromanganese, and silicomanganese, respectively. As a result, U.S. apparent consumption of manganese increased by an estimated 61.8% to 720,000 t in 2010. Exports of manganese ore increased by 20% to 18,000 t. According to Global Industry Analysts, Inc., the Asia-Pacific region represents the largest, fastest growing regional segment for manganese worldwide. Robust growth in the economies of several Asia-Pacific countries in the past decade, especially China and India, positively impacted the manganese market in the region. In 2009, China emerged as the largest producer of manganese in the world. However, most of the mineral produced in China is of low grade, and the country relies on imports for highgrade manganese. Asia-Pacific manganese consumption is projected to grow at a compound annual rate of 7.9% to 2015. Europe represents the second major market.4

Molybdenum In 2010, molybdenum, valued at about $885 million (based on average oxide price), was produced by eight mines in the U.S. Molybdenum ore was produced as a primary product at three mines (one each in Colorado, Idaho and Nevada), while five copper mines (three in Arizona and one each in Montana and Utah) recovered molybdenum as a byproduct. Three roasting plants converted molybdenite concentrate to molybdic oxide, from which intermediate products, such as ferromolybdenum, metal powder and various chemicals, were produced. Iron and steel and superalloy producers accounted for about 75% of the molybdenum consumed. U.S. mine output of molybdenum in concentrate in 2010 increased about 17.2% from that of 2009, to 56,000 t. Imports for consumption increased 66.7% to 19,000 t, while exports increased slightly to 28,000 t (from 27,900 t in 2009). Domestic roasters operated at between 80-90% of full production capacity in 2009, but in 2010 operated close to full production levels. U.S. reported consumption decreased CERAMIC INDUSTRY ³ January 2012

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DIGITAL EXCLUSIVE SPECIAL SECTION slightly from that of 2009, while apparent consumption increased 57.4% to 48,000 t. Mine capacity utilization in 2009 was about 82%. Molybdenum prices increased in the first half of 2010 but slowly started to decrease in the third quarter; however, molybdenum demand remained strong. Both byproduct and primary molybdenum production levels in the U.S. recovered in 2010 from their relatively low levels in 2009. According to Merchant Research & Consulting Ltd., approximately 35% of the worldwide molybdenum mined volume comes from China. In addition, the company reported that global molybdenum consumption was expected to grow 9% in 2011, with most of the demand coming from China. The growth in China’s steel market is forecast to outpace the average country’s GDP growth, which will impact the global price for molybdenum.5

Table 4. World rare earth demand (metric tons).

Niobium and Tantalum

Other countries

Merchant Research & Consulting Ltd. reported that the projected future for niobium producers looked positive, while the tantalum market is expected to experience difficulties due to major supply shortfalls. Forecasts for niobium demand are promising, as end users bring back suspended capacity. Recent mine closures have cut global tantalum supply by around 40%, and demand is forecast to increase only slightly. However, tantalum offers advantages over competitive materials that make it attractive in applications such as electronic capacitors.6 In 2010, companies in the U.S. produced ferroniobium and niobium compounds, metal, and other alloys from imported niobium minerals, oxides, and ferroniobium. Niobium was consumed mostly in the form of ferroniobium by the steel industry and as niobium alloys and metal by the aerospace industry. Apparent consumption increased dramatically (97.1%) to 8,300 t. U.S. niobium import dependence was expected to be the same as that of 2009, S7

Region

2010

2015

% Annual Growth

North America

12,800

17,000

5.8

Western Europe

10,300

13,700

5.9

Asia-Pacific

99,600

143,000

7.5

Central and South America

1,150

1,405

4.1

Eastern Europe

2,600

2,990

2.8

Africa/Mideast

1,550

1,905

4.2

128,000

180,000

7.1

Total Source: The Freedonia Group, Inc.

Table 5. World rare earth mine production and reserves (metric tons). Country

2009

2010*

% Change

Australia

0

0

0.0

Brazil

550

550

0.0

China

129,000

130,000

0.7

NA

NA

NA

2,700

2,700

0.0

350

350

0.0

0

0

0.0

NA

NA

NA

133,000

130,000

-2.3

Commonwealth of Independent States India Malaysia U.S. World total (rounded) *estimated NA = not available Source: www.usgs.gov

when Brazil was the leading niobium supplier. By weight in 2009, Brazil supplied 75% of total U.S. niobium imports, 69% of ferroniobium, 91% of niobium metal, and 86% of niobium oxide. U.S. imports for consumption in 2010 jumped 93.2% to 8,500 t, while exports dropped by 12.8% to 170 t. U.S. tantalum apparent consumption in 2010 was estimated to increase about 153.7% (to 1,200 t) from that of 2009. Tantalum was consumed mostly in the form of alloys, compounds, fabricated forms, ingot and metal powder. Tantalum capacitors were estimated to account for more than 60% of tantalum use. Major end uses for tantalum capacitors include automotive electronics, pagers, personal computers and portable telephones. Tantalum imports for consumption increased by 88.0% to 1,500 t. Tantalum waste and scrap was the leading imported tantalum material, accounting

January 2012 ³ WWW.CERAMICINDUSTRY.COM

for more than 42% of tantalum imports. By weight, from 2006 through 2009, tantalum mineral concentrate imports for consumption were supplied 66% by Australia and 21% by Canada; metal, 27% by China, 27% by Kazakhstan and 15% by Germany; and waste and scrap, 15% by China, 14% by Portugal, and 12% by Germany. U.S. exports of tantalum dropped 1.8% to 320 t in 2010.

Rare Earths Roskill Information Services reports that China is estimated to account for 94% of the world’s supply of rare earths in 2011, with most of the remainder coming from Russia and the U.S. By 2015, the rest of the world will account for just over a quarter of world supply; this proportion is likely to increase through 2020. Global demand for rare earths grew 5% per year between 2005-2010 (though the market shrank in 2009), according to Roskill. Growth in demand in China

was much higher, running at 11% per year. The country now accounts for 70% of world demand, which is estimated at 125,000 t in 2010. Consumption of rare earths in the rest of the world declined by nearly 4% per year during the same period. The decline was partly due to the impact of the recession, but also reflected the increasing volume of downstream processing within China and the tightening export quota. The structure of the rare earth industry is changing, not only in terms of the development of resources outside China, but also in the determination of companies both inside and outside China to become fully integrated into downstream products such as magnets and phosphors. There will continue to be a role for merchant producers supplying separated oxides, but it will be less prominent than in the past.7 According to The Freedonia Group, Inc., world demand for rare earths is forecast to expand 7.1% per year to 180,000 t by 2015 (see Table 4). In dollar terms, sales are expected to more than triple, from $3 billion in 2010 to $9.2 billion in 2015. Neodymium and dysprosium are expected to post the fastest growth rates of any rare earth types, spurred by increased sales of heatresistant NdFeB permanent magnets. However, cerium will remain the most widely used rare earth, accounting for almost one-third of the 2015 tonnage total.8 The estimated value of refined rare earths imported by the U.S. in 2010 was $161 million, an increase from $113 million imported in 2009. Based on reported data through July 2009, the estimated 2009 distribution of rare earths by end use, in decreasing order, was: chemical catalysts, 22%; metallurgical applications and alloys, 21%; petroleum refining catalysts, 14%; automotive catalytic converters, 13%; glass polishing and ceramics, 9%; rare earth phosphors for computer monitors, lighting, radar, televisions, and X-ray intensifying film, 8%; permanent magnets, 7%; electronics, 3%; and other, 3%.

U.S. imports of rare earth materials in 2010 included: rare earth metals (alloy), up 33% to 250 t; cerium compounds, down 6.7% to 1,400 t; mixed rare earth oxides, down 1.1% to 4,700 t; rare earth chlorides, up 82.5% to 750 t; rare earth oxides (compounds), down 45.3% to 2,800 t; and ferrocerium (alloys), down 13.9% to 87 t. Exports included: thorium ore (monazite or various thorium materials), down 94.4% to 1 t; rare earth metals (alloys), down 87% to 640 t; cerium compounds, flat at 840 t; other rare earth compounds, up 31.9% to 600 t; and ferrocerium (alloys), down 5.7% to 2,800 t. Table 5 shows rare earth world mine production and reserves.

Silica Industrial sand and gravel (often called silica, silica sand and quartz sand) valued at about $777 million was produced by 68 companies from 124 operations in 34 states in 2010. Leading states (in

order of tonnage produced) were Illinois, Wisconsin, Texas, Oklahoma, Louisiana, Minnesota, Michigan and California. Combined production from these states represented 59% of the domestic total. Total U.S. production in 2010 increased by 60% to 26.5 Mt. About 31% of the U.S. tonnage was used as glassmaking sand, 25% as hydraulic fracturing sand and wellpacking and cementing sand, 13% as foundry sand, 8% as whole-grain silica, 7% as whole-grain fillers and building products, 4% as golf course sand, 3% as ground and unground silica for chemical applications, and 9% for other uses. Apparent consumption increased slightly (4.3%) to 24 Mt in 2010. Exports rose to 2.6 Mt (up 20.9%), while imports for consumption increased by 15.8% to 110,000 t. Imports of silica are generally of two types—small shipments of very high-purity silica or a few large shipments of lower grade silica CERAMIC INDUSTRY ³ January 2012

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DIGITAL EXCLUSIVE SPECIAL SECTION shipped only under special circumstances (e.g., very low freight rates).

Soda Ash The total value of domestic soda ash (sodium carbonate) produced in 2010 was estimated to be about $1.3 billion. The U.S. soda ash industry comprised four companies in Wyoming operating five plants, one company in California with one plant, and one company with one mothballed plant in Colorado that owns one of the Wyoming plants. The five producers have a combined annual nameplate capacity of 14.5 Mt. Total U.S. production in 2010 increased by 7.4% to 10 Mt. Based on final 2009 reported data, the estimated 2010 distribution of soda ash by end use was glass, 46%; chemicals, 29%; soap and detergents, 10%; distributors, 6%; flue gas desulfurization and miscellaneous uses, 3% each; pulp and paper, 2%; and water treatment, 1%. Apparent consumption increased slightly (1%) to 5 Mt. In the third quarter of 2010, domestic soda ash production and export sales increased, especially to South America and Southeast Asia. The U.S. soda ash export association raised the export price by $30 per ton effective October 1, citing that global soda ash demand was improving. U.S. imports for consumption skyrocketed by 400% in 2010, to 30,000 t. Exports increased by a more sedate 13.4% to 5 Mt. According to Merchant Research & Consulting Ltd., flat glass and detergents will remain the key market driver for soda ash in both emerging and developed economies. Container and flat glass production are forecast to experience an annual growth rate of approximately 3%, which will positively impact demand for soda ash. India, China and other lowcost manufacturing markets remain key regions for soda ash demand. 9 The adverse economic conditions throughout most of the world are forecast to improve beginning in 2011. Notwithstanding the continuing economic and energy problems in certain areas of S9

the world, overall global demand for soda ash is expected to grow 1.5-2% annually for the next several years. If the domestic economy and export sales improve, U.S. consumption may be higher in 2011.

Talc and Pyrophyllite Domestic talc production in 2010 increased by 3.7% to 530,000 t valued at $15 million. Three companies operated six talc-producing mines in three states in 2010. These three companies accounted for more than 99% of the U.S. talc production. Three other companies (two in California and one in Virginia) worked from stocks. Montana was the leading producer state, followed by Texas and Vermont. Apparent U.S. consumption of talc in 2010 increased by 3.8% to 460,000 t. Sales of talc were estimated to be 562,000 t, valued at $66 million, a 9.8% increase over 2009 levels. The total estimated use of talc in the U.S. (including imported talc) was: • plastics, 24% • ceramics, 18% • paint, 16% • paper, 15% • cosmetics and roofing, 6% each • rubber, 3% • other, 12% About 170,000 t of talc was imported (a 41.7% increase), with more than 75% of the imported talc being used for plastics, cosmetics, and paint applications (in decreasing order by tonnage). Exports increased by 27.7% to 240,000 t. One company in California and one company in North Carolina mined pyrophyllite. Production of pyrophyllite increased slightly from that of 2009. Consumption was chiefly in refractory products, ceramics and paint (in decreasing order by tonnage).

Titanium and Related Materials The value of titanium mineral concentrates consumed in the U.S. in 2010 was about $470 million. Estimated consumption increased by 10.3% over 2009 levels, to 1.5 Mt. Zircon was a co-product of mining from ilmenite and rutile deposits. About 94% of titanium mineral concen-

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trates was consumed by domestic titanium dioxide (TiO2) pigment producers. The remaining 6% was used in welding rod coatings and for manufacturing carbides, chemicals, and metal. Production of titanium mineral concentrates remained flat in 2010, at 200,000 t. Imports for consumption increased 32.7% to 1.2 Mt, and exports increased as well, to 11,000 t (up 22.2%). Two firms produced ilmenite and rutile concentrates from surface-mining operations in Florida and Virginia. One of the mineral producers acquired land that will extend mining operations near Starke, Fla., though 2017. The life of the Stony Creek, Va., operation was recently extended to 2015 through the addition of the Brink deposit. In Mozambique, plans were announced to expand ilmenite production capacity at the Moma mining operation to 1.8 Mt/year, a 50% increase compared with the existing design capacity. In 2010, TiO 2 pigment valued at about $3 billion was produced by four companies at six facilities in five states. The estimated use of TiO2 pigment by end use was paint (includes lacquers and varnishes), 59%; plastic, 26%; paper, 9%; and other, 6%. Other uses of TiO2 included catalysts, ceramics, coated fabrics and textiles, floor coverings, printing ink and roofing granules. Apparent U.S. consumption of TiO2 in 2010 increased by 4.0% to 786,000 t. Domestic production of TiO2 climbed 13.8% to 1.4 Mt in 2010. Imports for consumption increased to 197,000 t (up 12.6%), while exports increased by 25% to 811,000 t. According to TZ Minerals International Pty. Ltd., global TiO2 pigment demand in 2010 was estimated at 5.3 Mt, up 12% from 2009. Regionally, the main consuming markets for TiO2 pigment are the major industrialized economies of North America, Europe and, increasingly, China. Per capita consumption is highest in North America and western Europe. The greatest opportunities for growth lie in the less developed high-population economies, led by China and India.10

Tungsten Roskill Information Services reports that, despite the steep drop in demand for tungsten, global output increased to an estimated 61,500 t in 2009. This was almost entirely due to an increase of 7,500 t in China, where consumption of tungsten continued to increase despite the economic problems elsewhere in the world. Production jumped again to almost 70,000 t in 2010 on the back of a further increase in Chinese output. Global mine output of tungsten is forecast to grow from 72,000 t in 2011 to around 100,000 t by 2016. Roskill expects to see a market fluctuating around equilibrium level, but forecasts a deficit in both 2011 and 2012, before new supply enters the market. Currently, 2013 is expected to be the tipping point where supply overtakes demand in the tungsten market at some point during the year. Assuming that the majority of planned projects reach production, a surplus is expected to develop. Any further delays to new supply entering the market would quickly see a deficit forming, and prices would remain higher than in the forecast (probably into 2014).11 In the U.S., exports of tungsten concentrate skyrocketed 952.6% in 2010 (to 400 t), while exports of other forms of tungsten increased by 46.5% to 4,000 t. Meanwhile, imports of tungsten concentrate dropped 16.4% (to 3,000 t) and imports of other forms of tungsten increased by 45.1% (to 9,300 t). Apparent consumption of all forms increased by 20.7% to 14,000 t, with an estimated value of $500 million.

Zirconium U.S. imports of zirconium ores and concentrates (zirconia content) increased by 23.8% in 2010, to 11,600 t, while imports of zirconia (ZrO2) dropped by 15.7% to 2,370 t. However, exports of zirconium ores and concentrates increased by 32.3% to 34,000 t, and zirconia exports jumped by 100.3% to 6,110 t. Global consumption of zirconium silicate (zircon) rebounded strongly in 2010, reaching 1.33 Mt, according to

Table 6. World zirconium mine production (thousand metric tons). Country

2009

Australia

476

481

1.1

Brazil

18

18

0.0

China

130

140

7.7

India

31

31

0.0

Indonesia

63

60

-4.8

South Africa

392

390

-0.5

Ukraine

35

35

0.0

U.S.

W

W

W

Other

19

30

57.9

1,160

1,190

2.6

World total (rounded)

be negatively affected by higher prices and substitution.12 

2010* % Change

*estimated W = withheld Source: www.usgs.gov

Roskill Information Services. Growth over the last decade has come mainly from the ceramic and chemical sectors, growing by 4.1% and 7.5% per year, respectively, compared to overall market growth of 2.6% per year. China now accounts for over half of total consumption, with the wider Asian region accounting for two-thirds of consumption. Other major ceramicproducing countries, such as Spain and Italy, are also large consumers of zircon. Growth in zircon production has lagged consumption since the early 2000s, but an almost doubling in zircon prices during 2004-2006 put more emphasis on primary zircon production. (Zircon has historically been a byproduct of titanium mineral extraction, and output has long been constrained by titanium mineral demand.) New deposits entering production (e.g., Victoria and South Australia) are being mined primarily for their zircon content. Table 6 details worldwide zirconium mine production. Future demand for zircon is forecast to increase by 5.4% per year, led by ceramics and chemical output in China. Recovery in demand from Western markets is likely to be protracted, particularly in the ceramic sector. Other end uses are forecast to show little growth and could

Editor’s note: The foregoing information, except where noted, was compiled from the U.S. Geological Survey (www.usgs.gov). All units are in metric tons except where otherwise noted. In most cases, 2010 data were the latest available. For additional details regarding the uses of these materials in the ceramic, glass and related industries, visit the Materials Handbook pages in this issue. References 1. Bauxite and Alumina: A Global Strategic Business Report (published February 2011, $4,200), Global Industry Analysts, Inc., www.strategyr.com. 2. Feldspar Market Review (published January 2011, $790), Merchant Research and Consulting Ltd., http://mcgroup.co.uk. 3. Graphite Market Review (published February 2011, $950), Merchant Research and Consulting Ltd., http://mcgroup.co.uk. 4. Manganese: A Global Strategic Business Report (published February 2011, $4,500), Global Industry Analysts, Inc., www.strategyr.com. 5. Molybdenum Market Review (published February 2011, $1,090), Merchant Research and Consulting Ltd., http://mcgroup.co.uk. 6. Tantalum and Niobium (Columbium) Market Review (published February 2011, $1,390), Merchant Research and Consulting Ltd., http://mcgroup.co.uk. 7. Rare Earths and Yttrium: Market Outlook to 2015 (published November 2011, $7,500), Roskill Information Services, www.roskill. co.uk. 8. World Rare Earths (published July 2011, $5,900), The Freedonia Group, Inc., www. freedoniagroup.com. 9. Soda Ash: 2011 World Market Outlook and Forecast up to 2016 (published October 2011, $4,500), Merchant Research and Consulting Ltd., http://mcgroup.co.uk. 10. Global TiO2 Pigment Producers Comparative Cost and Profitability Study, TZ Minerals International Pty. Ltd., www.tzmi.com. 11. Tungsten: Market Outlook to 2016 (published August 2011, $7,500), Roskill Information Services, www.roskill.co.uk. CERAMIC INDUSTRY ³ January 2012

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ABRASIVES

³

ALUMINA

Materials Handbook

2012 Materials Handbook

A

BRASIVES. Substances used to grind, shape or polish another material. Abrasives used in the ceramic industry can be classified as either conventional abrasives or superabrasives. The size, shape, hardness and friability of an abrasive particle determine its characteristics as an abrasive. Coarse, larger grains normally remove material faster than smaller grains, which usually give better surface finish. Conventional abrasives can be silicon carbide, aluminum oxide, boron carbide, tungsten carbide, hardened steel and coated tools. Silicon carbide, also called carborundum, aluminum oxide and boron carbide, a compound of boron and carbon, are crystals used for making grinding wheels. Coated products are being used in tools like saw blades and drill tips, while tungsten carbide and hardened steel are used for machining or turning applications. Superabrasives, by their very name, are abrasives that are of superior hardness to conventional abrasives and, as such, provide extended tool life and can grind or machine at higher rates with better finishes and no workpiece damage. Natural diamonds were the first superabrasives, followed by the creation of synthetic diamonds in 1955, cubic boron nitride in 1957, polycrystalline diamond in 1970 and polycrystalline cubic boron nitride shortly thereafter. Cubic boron nitride (CBN) is not found in nature and is second in hardness to diamond. Because of its physical properties, it is used for grinding hard ferrous materials. Polycrystalline diamond and CBN consist of a layer of many crystals of diamond or CBN integrally bonded to a carbide substrate. The abrasion resistance of the diamond or CBN coupled with the strength of the carbide present an extremely effective cutting tool. Diamond is by far the hardest and strongest of all abrasives available. As such, it is the superior abrasive of choice for grinding, machining and sawing of materials such as ceramics, glass, concrete, natural stone, cemented carbides, nonferrous metals and other non-metallic materials. However, because diamond is an allotrope of carbon, it inherently reacts with ferrous metals at the typical temperatures encountered in the material removal process. The resulting rapid wear of diamond abrasives make them generally uneconomical in grinding ferrous metals, except in certain low-speed honing applications. Cubic boron nitride would be the recommended abrasive for ferrous metals. In machining or turning of ceramic materials, polycrystalline diamond would be the most effective abrasive to choose. Conventional abrasives. Both aluminum oxide and silicon carbide abrasives have properties that make them an integral part of the entire family of ceramic materials. As such, their utility is limited in comparison with that of diamond. The hardness of conventional abrasives may be below, equal to, or marginally higher than the ceramic material, leading to inefficient grinding. All high-production grinding that also demands a significant level of precision and control over all aspects of the ground surface is carried out today with diamond abrasives. The use of conventional abrasives, on the other hand, is limited to roughing, finishing and cutting off relatively easy to machine materials, where precision and finish are not major requirements. ABRASIVE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

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ADDITIVES, CHEMICAL. Chemical additives contribute to the processing of different raw materials in order to achieve reproducible results and manufacture high-quality products via the technological steps of preparation, shaping, glazing and decorating. Types of chemical additives used in ceramics include decorating aids, deflocculants, dispersants, glaze additives, porosity-inducing agents, pressing agents, lubricants, release oils, rheological additives, setting accelerators, tape casting additives, injection molding binders, water glass hardeners and wetting agents. ADDITIVES, CHEMICAL SUPPLIERS ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com ALUM. A potassium aluminum sulfate KAl(SO4)2·12H2O or an ammonium aluminum sulfate NH4Al(SO4)2·12H2O. (See also BINDERS.) ALUM SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com ALUMINA. Al2O3. Mol. wt. 101.94; sp. gr. 3.4-4.0. A material appearing in several crystalline forms, of which alpha-Al2O3 is the densest and most stable. At least four hydroxides or hydrates are known. Alpha-Al2O3 belongs to the trigonal system, refractive index 1.765. It is insoluble in water and only slowly soluble in alkalies and strong mineral acids, but is attacked by hydrofluoric acid and potassium bisulfate. The alpha form of alumina melts at 2040°C (3704°F). In sintering, this permits the discrete crystallites to react with each other to form the large crystals making up the sintered mass. Mineralizers or fluxes permit sintering at lower temperatures. The sintered bodies take on the properties of the basic material. In 100% Al2O3 bodies, mechanical failure will occur through the alumina grains as readily as at grain boundaries. Native alumina is found as the mineral corundum (Mohs hardness 9.0), long used as an abrasive and for such jewels as ruby and sapphire. The hydrated minerals, gibbsite, diaspore and boehmite also are found in nature. Although alumina occurs commonly combined as silicates in clays, feldspars, kyanite and many other minerals, the principal sources of purified alumina and hydrated alumina are native bauxites and laterites, from which large tonnages are extracted annually by the Bayer process. Bayer aluminas are available in a wide range of physical properties mainly as a result of control of crystal size and chemical activity during their formation. Their high purity with respect to iron and fluxing impurities makes them suitable for many ceramic applications in the refractory, abrasive and alumina porcelain fields. Six types of alumina are generally considered for use in ceramic products: Activated alumina is a highly porous (about 200-400 m2/g surface area), granular form of Al2O3 used as a catalyst, catalyst carrier and adsorbent. It is chemically inert to most gases, and will not swell, soften or disintegrate in water. It exhibits high resistance to thermal and mechani-

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cal shock and abrasion, and will hold moisture without change in form or properties. The crystalline structure is normally chi, eta, gamma and/or rho alumina. Synthetic boehmite alumina is a monohydrate-type alumina commercially produced in large volumes for applications in the catalyst industry as well as in sol-gel ceramics. Its properties differ significantly from those of the “trihydrate.” Boehmite or pseudoboehmite alumina can be made by at least two routes. First, and leading to the most pure alumina, is via aluminum alkoxide hydrolysis. The alumina produced can be dispersed to the sol state by the addition of an aqueous acid or, in some cases, water. Seeding with various other inorganics (Messing or Roy technology) is one way to produce “ceramic” aluminas. The formula is Al2O3-xH2O, where x varies from 1-1.8 depending on alumina crystallite size. Boehmite alumina also can be synthetically prepared by the hydrothermal treatment of gibbsite from the Bayer process. The alumina is produced by crystallization at controlled pH in the presence of an appropriate seed material. Alumina applications. Alumina is used to control matteness or texture in glazes. The best alumina-to-silica ratio in conventional glazes has been found to be between 1:6 and 1:10. In glazes containing at least 0.1 equivalent of alumina, the further addition of alumina raises the deformation or maturing point. A very important function of alumina is its prevention of glaze devitrification. Alumina increases viscosity, refractoriness and opacity. In general, it increases resistance to chemical attack and weathering, impact resistance, tensile strength, hardness. The chief sources of alumina equivalents for glazes are feldspar, clay, Cornwall stone and nepheline syenite. Alumina is added to glazes or underglazes to aid the development of pink colors of the Cr-Al, Mn-Al type. A small addition of alumina hydrate enhances the color of Cr-Al pink making it more red in tone. Addition of alpha alumina to pink underglazes of the Mn-Al type helps overcome blistering tendencies due to migration of manganese. Fine grinding is essential. The alumina equivalent in enamels is usually introduced in the form of feldspar, clay and nepheline syenite, or cryolite; frequently as pyrophyllite in zirconia-opacified enamels; and as hydrated or calcined alumina. In zirconia enamels the alumina is commonly added as feldspar, 6-25%; alumina hydrate, 0-7%; cryolite, 0-17%; or kaolin, 0-10%; with the usual mill addition of 6-7% clay. The equivalent alumina content of this type of enamel usually varies from about 5% to 12%, but even enamels containing alumina as high as 14% of the theoretical melted composition remain very fluid at smelting temperatures. Usually feldspar is considered to be the principal source of alumina in enamel formulations. The maximum permissible amount of feldspar is restricted by the desired alkali content of the formula. Additional alumina is added as clay to the limiting silica content. After adding cryolite to obtain the desired opacity, the remaining alumina required by the formula, after all other considerations have been met, is furnished usually as Bayer alumina hydrate. Alumina promotes opacity in zirconia enamels. It is used to increase brilliance, bonding power, durability and resistance to abrasion. The reflectance of some zirconia enamels can be increased by replacing part of the zinc oxide content with an equal weight of alumina. The tearing tendency increases toward the lower limit of alumina content and a tendency toward matteness is common when the upper limits are approached. Alumina is injurious to the appearance of enamels when used to such an extent as to produce opacity, because it then affects the homogeneity of the enamel. The opacification in such cases depends not on the presence of undissolved or precipitated alumina compounds, but on the presence of gas bubbles. Yet, enamel coatings for highSupplier listings indicate paid advertising.

2012 Edition

temperature protection of steel have been developed at the National Institute of Standards & Technology which contain as much as 24% alumina, of which 18.5% is contributed by Bayer alumina. These coatings exhibit no tendency to reboil, i.e, for gas bubbles to appear at about 590°C upon reheating the formed enamel. When an enamel contains enough alumina to make it too viscous to flow, the addition of 2-3% whiting (calcium carbonate) reduces the viscosity sufficiently that the enamel will flow more freely. Enamels high in alumina tend toward devitrification and crazing. It is said that between the limits of 0.09 and 0.19 equivalents, very fine, white, glossy and adhesive enamels are formed. The quantity of alumina necessary for good gloss, however, depends largely on the other constituents of the batch. In glass the alumina equivalent is commonly supplied by feldspar, but there is a growing use of the somewhat similar nepheline syenite, which has a higher equivalent alumina content. Calcined or hydrated Bayer alumina is used where exceptional freedom from iron is desired. Kyanite may be used, and cryolite is a source for the manufacture of opal glass. Some claim that alumina in the glass batch renders melting more difficult; others take the opposite view. This difference of opinion seems to be largely a result of assumed temperature conditions, for a soda-lime glass held at 1200°C is retarded in melting by the addition of alumina, whereas the same batch at 1350°C melts slightly faster with the alumina than without. In continuous fiberglass, china clay or kaolin is often used in place of alumina because of the former’s low alkali and iron contents. The addition of alumina may make both melting and fining easier. Springer proved that this is the case for glasses rich in lime and correspondingly low in alkalies, while exactly the opposite occurs when any alumina is added to highalkali glasses and also to glasses where lime and alkali are present in approximately molecular proportions. Morey has shown that the substitution of alumina for 2% of lime caused a sharp drop (80°C) in the liquidus temperature in a glass composed of 14.3% soda, 11.0% lime and 74.7% silica. Alumina has no marked effect on the melting of heavy lead glasses, but resistance to shock is greatly increased. The presence of alumina is necessary in glasses opacified with fluorine compounds. Blau, Silverman and Hicks report that alumina in opal glass makes for greater fluorine retention, not necessarily greater opacity. According to Alpert, alumina gives more durable and more elastic glass by permitting replacement of a portion of the alkali by lime. Frink says that the homogenization of glass from tank furnaces is improved by the presence of 3% alumina, and that alumina will set a glass more suddenly and will produce a skin which does not take on mold imperfections. It greatly reduces the coefficient of expansion, increases the tensile strength, makes the glass harder and more resistant to abrasion, and improves luster. When alumina is substituted for lime or magnesia, a reduction is brought about in annealing temperature in every case, according to Turner and English, but the reduction is pronounced only when the substitution exceeds 6-7%. The tendency for the formation of such faults as cords, reams and striae can be greatly reduced by moderate additions of alumina. Ferguson and others claim that alumina provides a longer working range and decreases devitrification, making the glass more suitable for machine operation. It increases resistance to weathering and attack by acids and steam, and when replacing silica it makes a more ductile and elastic glass. According to Parmalee and Harman, surface tension of soda lime glasses may be increased as much as 7% by the addition of 2% alumina, the increase being substantially linear between 2 and 8% alumina. Lyle, Horak and Sharp found that the chemical durability of soda-lime glass was improved by the addition of 1.5-2.5% alumina, the greatest benefit occurring when the alumina is one-eighth the soda content. For ordinary commercial

ALUMINA

soda-lime glasses, up to 3% alumina can be used advantageously from the standpoint of resistance to weathering, decreased tendency to devitrification and lowered thermal expansion. In these glasses the alumina is usually furnished by feldspar and is substituted in place of lime and magnesia. Alumina, combined with boric acid, is an important constituent of all types of low expansion glasses for use in chemical ware, cooking ware and thermometers, in amounts up to 7%. In low-alkali borosilicate glasses, the alumina is furnished by kyanite or Bayer alumina. The alumina equivalent of conventional pottery and whiteware is usually brought in with feldspar, kaolin and ball clay. The addition of Bayer alumina to porcelain compositions, substituted for part of the flint in amounts from 7 to 20% or higher, tends to increase refractoriness and give a longer firing range. The unfavorable effects caused by quartz inversion of the flint in the composition are largely reduced, thus allowing less critical firing schedules. Body strength improves markedly but opacity increases. Fused alumina, although not as hard as silicon carbide and some other synthetic abrasives, is superior in toughness and is particularly recommended for metal grinding. The addition of alumina to fireclays increases refractoriness, load-bearing ability and spalling resistance. A type of high-temperature insulating refractory is made from fused alumina bubbles, or hollow spheres, bonded and high fired. This material is supplied as a castable which can be formed into the desired shape on the job and provides protection up to 3300°F. Calcined alumina and bauxite, as well as tabular alumina grog, are used in large tonnages to increase the alumina content of refractories. Calcined, sintered and fused aluminas constitute the base materials in a class of special refractories containing from 90-99% alumina, used in the form of refractory brick or monolithic liners. Calcined alumina is added to native kyanite to adjust the alumina-silica ratio during conversion to mullite. High-purity synthetic mullite is produced from alumina and low-iron clays mixed in suitable proportions to form 3Al2O3-2SiO2, and converted by sintering or fusion. A synthetic, high-temperature thermal insulator consists substantially of mullite in the fibrous form. Alumina is used in producing refractory calcium aluminate cements which set by hydraulic bonding. In rammed and castable compositions with refractory grogs, these cements retain good bonding strength in their effective service range. Calcium aluminate cements, prepared from Bayer alumina may have pyrometric cone equivalents above 35. There are three grades of calcium aluminate (CA) cement: low, intermediate and high purity. High purity CA cement incorporates alumina to achieve its refractoriness. The other two grades use a bauxite-limestone mixture to achieve the desired level of alumina in the finished cement. Alumina has a wide diversity of uses and potential for ceramics. For electronic and aerospace applications, its outstanding mechanical strength, excellent thermal shock resistance, excellent electrical properties (high dielectric strength, low power factor, etc.), and its chemical and abrasion resistance make it well suited in this field. Uses for high-alumina ceramics include electronic tube parts, ceramic-to-metal seals, semiconductor and IC substrates, highfrequency insulators, holders and spacers for printed circuits, radomes, missile nose cones and spark plug insulators. Mechanical uses for high-alumina bodies include seal surfaces for mechanical rotary seals for pumps and similar equipment, plungers or liners in reciprocating pumps, nozzles, rock bits, cutting tools, nonlubricated high-temperature roller bearings, and a wide variety of other mechanical parts. High-alumina ceramics are fired ceramic compositions in which the major crystal phase is alpha alumina or corundum. The aluminum oxide content is usually 75-100% and the parts are fired at temperatures ranging from 2600-3200°F, or higher, on a commercial scale. Material is available in both the vitrified and sintered forms.

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Alumina ceramics can be glazed when maintaining surface cleanliness is a requirement and are readily metallized. There are many commercial grades of alumina powder available in calcined, tabular or fused form. Alumina is used for high-purity applications, electronic applications, cermet compositions and flame sprays as a coating. High Al2O3-containing bodies are also available that conform to the standard C 786, C 795 and C 799 of DIN 60672-1 with 92%, 94%, 96% and 99% Al2O3. These ready formulated raw materials are ready for pressing and can be formed directly into ceramic tiles via axial or cold isostatic pressing. The ceramic bodies are produced depending on their application by quality control of green and sintered density, shrinkage, porosity, loss of ignition and granulate size. The properties of the Al2O3 (corundum) are tailored to the application area in which the material is used such as wear resistance, high temperature stability, good electrical insulation, thermal conductivity and corrosion resistance. Ceramic bodies with 92% Al2O3 predominate wear resistance applications. Low electrical conductivity and dielectric loss with simultaneous good mechanical properties and thermal conductivity is obtained from ceramic bodies with 96% Al 2O 3. The highest demands of high bend strength, thermal shock resistance, resistance to acid and alkali conditions, abrasion and wear resistance requires the qualities of 99% Al2O3 ceramics. The ceramic bodies can be used by an addition of approximately 25% water for slip casting or even as an extrusion mix by addition of a suitable plasticizer. Properties As compared with other ceramic materials, alumina ceramics are superior mainly in regard to strength, impact resistance and hardness, as illustrated in Table 1.

The hardness of aluminum oxide compositions, which makes them suitable for abrasion-resistant applications, cutting tools, etc., is greater than many materials normally considered hard (see Table 2).

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ALUMINA,CALCINED

Materials Handbook ALUMINA SUPPLIERS CONTINUED

Resistance to Temperature High-alumina bodies are extremely temperature resistant, depending upon the percentage of alumina present, and upon their original firing temperature. Bodies containing 95% Al2O3 usually retain 90% of their tensile strength at temperatures up to and sometimes above 2000°F. For many of the mechanical and some of the electrical applications of alumina, isostatic or hydrostatic pressing is used. Blanks are initially produced by pressing dry powder in a rubber sack or mold under high hydraulic pressure. Uniform compaction and homogeneity are obtained by this application of uniform pressure from all directions, and a true and accurate inside contour can be formed by pressing the powder around a metal arbor or mandrel. The outside shape is formed by machining the pressed blanks. Fired parts, although extremely hard, can be ground by diamond wheels or diamond tools, and tolerances of 0.001 in. are readily obtainable. By using lapping techniques, tolerances of 0.0001 in. also are obtainable, but the cost involved is relatively high. In high temperature coatings, alumina is added to increase refractoriness. A typical coating would have this composition: Hard member (commercial frit) . . . . . . . . . . . . . . . 50 lb Soft member (commercial frit) . . . . . . . . . . . . . . . 50 lb Calcined alumina . . . . . . . . . . . . . . . . . . . . . . . . . 50 lb Clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 lb Cobalt oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 lb Borax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 oz Citric acid crystals . . . . . . . . . . . . . . . . . . . . . . . 22 gal Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 g Fusion of the low-temperature ground coat frit protects the metal from excessive oxidation at elevated temperatures, while the alumina aids in the formation of a refractory (heat-resistant) coating. Coatings of this type resist combustion products and minimize oxidation over a temperature range of 1000-1400°F. They are used on truck exhaust pipes and jet engine combustion liners, compressor blades and tank mufflers. In transfer molding, alumina is mixed with a small amount of powdered resin, preheated and then injected into heated single-cavity or multiple-cavity dies. The resin burns out during firing. ALUMINA SUPPLIERS

C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA, ACTIVATED. Activated alumina is a highly porous, granular form of alumina used as a catalyst, catalyst carrier and adsorbent. (See ALUMINA.)

ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA BODIES. These specially formulated raw materials are ready for pressing and can be formed directly into tiles or other shapes via axial or cold isostatic pressing. Ceramic bodies with 92% Al2O3 are used primarily in wear-resistant applications; bodies with 96% Al2O3 exhibit low electrical conductivity and dielectric loss with good mechanical properties and thermal conductivity; and bodies with 99% Al2O3 exhibit high bend strength along with extremely high thermal shock resistance, acid and alkali resistance, and abrasion and wear resistance. ALUMINA BODIES SUPPLIERS

ALMATIS 501 W. Park Rd. Leetsdale, PA 15056 (800) 643-8771; (412) 630-2800 Fax: (412) 630-2900 Email: [email protected] Website: www.almatis.com NABALTEC AG Alustrasse 50-52, Postfach 18 60 D-92409 Schwandorf Germany (49) 9431-53-391 Fax: (49) 9431-61-557 Email: [email protected] Website: www.nabaltec.de

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Source: C-E Minerals, www.ceminerals.com/bubblealumina.pdf.

ALUMINA, BUBBLE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com

ALUMINA, ACTIVATED SUPPLIERS

Source: Nabaltec, www.nabaltec.de.

ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com

als, refractory lightweight bricks and as loose bulk material for the filling of thermal insulation walls, as well as a filtration medium for aggressive liquids or melts.

ALUMINA, BUBBLE. Bubble alumina is produced by fusing high-purity alumina and atomizing the melt with compressed air to create hollow spheres. The resulting product is hard but extremely friable with respect to its pressure strength. Its melting point is approximately 2100°C. Due to its hollow spheres, bubble alumina has a low bulk density and extremely low thermal conductivity. Chemically inert, it is used for the production of refractory insulation materi-

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WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com ALUMINA, CALCINED. Calcined aluminas are available in numerous grades based on the degree of calcination (as measured by the crystal size and specific surface area) and Na2O content (<0.01 to nominally 0.5%). Fully calcined aluminas are primarily alpha phase aluminas. Incomplete thermal conversion to the alpha phase results in the presence of transitional alumina phases being present in the aluminas and result in a higher measured surface area. Unground calcined alumina is composed of agglomerated crystallites which are nominally in the 100 to 325 mesh size range. Grinding separates the agglomerates into nearly individual crystallites that are less than 325 mesh. Various levels of grinding are available, from a light breaking of agglomerates to a heavy ball milling. Water-based ground calcined alumina slips can be deflocculated with hydrochloric or nitric acid or with alumina chloride in the region of pH 3.5-4.5. The surface charge under these conditions is positive with the anions acting as counterions. Acids having polyvalent anions (e.g. sulfuric acid) are not satisfactory deflocculants for alumina owing to the close approach of the multiple-charged anions to the positively charged surface. As the pH of alumina slips is increased, the surface charge diminishes until, at pH 8-9, there is no charge and the slip is strongly flocculated. However, if the pH is raised to 11-12 with additions of alkali hydroxide or hydrolyzable alkali salt, the particle becomes negatively charged with alkali cations as counterions, and the slip is again deflocculated. At pH 7-9 alkali polyelectrolytes can be used to deflocculate alumina slips. Increasing the concentration of polyanions causes formation of hemimicelles on adsorption sites and the particle surface-charge reverses from positive to strongly negative, with alkali cations and counterions. Alumina slips prepared from narrow distributions tend to be dilatant. However, when several different narrow distributions of alumina are blended to form extended distributions similar to clay body distributions, slip properties resembling those of clay slips may be obtained. Supplier listings indicate paid advertising.

2012 Edition

ALUMINA, CALCINED

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ALUMINA, HYDRATED

ALUMINA, FUSED SUPPLIERS CONTINUED ALUMINA, CALCINED SUPPLIERS

advantage of alumina fiber’s high strength and modulus, especially at elevated temperatures; low electrical conductivity; high thermal conductivity; chemical inertness; and wear resistance. Typical fiber properties are shown in the table below. WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com

ALMATIS 501 W. Park Rd. Leetsdale, PA 15056 (800) 643-8771; (412) 630-2800 Fax: (412) 630-2900 Email: [email protected] Website: www.almatis.com

ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com

RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA, CHROME. Chrome alumina (fused) is produced by the electric furnace fusion of Bayer process alumina and chromic oxide. The amount of Cr2O3 typically added can be varied from 0.3% to 2% for grinding wheel applications and from 20% to >95% for refractory applications. As the amount of Cr2O3 increases, the color goes from lavender to pink to ruby to dark red to green. Typical applications for fused chrome alumina are grinding wheels for precision grinding, and as a refractory raw material for making refractories for the steel and fiberglass industries. ALUMINA, COLLOIDAL. Colloidal alumina is an aqueous dispersion of nanometer-sized alumina particles. The alumina particles are treated with an acid to produce a positive surface charge, which causes the particles to repel each other, resulting in a stable sol. Colloidal aluminas are useful in numerous applications, such as bonding inorganic fibers and powders, and infiltration rigidizing refractory fiber shapes for high-temperature applications. ALUMINA, COLLOIDAL SUPPLIERS WESBOND CORP. 1135 E. 7th St. Wilmington, DE 19801 (302) 655-7917 Fax: (302) 656-7885 Website: www.wesbond.com ALUMINA FIBERS, POLYCRYSTALLINE. A family of commercially available ceramic fibers containing at least 85% Al2O3. Targeted uses include reinforcement of ceramic-, glass-, metal- and resin-matrix composites; high temperature insulation; catalyst supports; molten metal filters; and wear-resistant components. These applications take

Other properties include a CTE of 6.8-8.8 x 10-6/°C and thermal conductivity of 26.7 kcal/m•h•°C. In epoxy composites reinforced with alumina fibers, compressive strengths of 200,000-350,000 psi and dielectric constants of 4.2-5.3 at 10 GHz have been measured. All commercial alumina fibers are spun from solutions or slurries of alumina precursors using conventional fiber forming technology, followed by staged heat treatment. Available forms include continuous, multifilament yarns and short fiber products. While the fibers are quite brittle with maximum strains of less than 1%, techniques have been developed to weave, braid and filament wind them into composite preforms. Papers and mats also have been made. ALUMINA, FUSED. Fused aluminas are produced by melting calcined alumina at above 2040°C (3700°F) in an electric arc furnace. Lower grades of fused aluminas use bauxite as feed to the electric furnace. Some TiO2 may be added to increase grain toughness. Tabular and fused aluminas are available in grain size from 0.5 in. to -325 mesh. ALUMINA, FUSED SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com

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ALUMINA, HIGH-PURITY. Al2O3. Mol. wt. 101.94; sp. gr. 3.98 g/cm3. A family of very high purity calcined aluminas derived from non-Bayer processes such as ammonium aluminum sulfate (alum-derived alumina), aluminum chloride or aluminum alkoxide. Purities higher than 99.99% can be obtained via these processes. High purity aluminas are used in single crystal YAG and sapphire growth operations; in the manufacture of translucent alumina tubes for sodium vapor lamps; for transmission sensitive optical applications; for high strength structural and engineered ceramics; and in electronic ceramics requiring zero alpha particle emission specifications. High purity aluminas are manufactured in a broad range of surface areas from a pure gamma alumina (140 m2/g) to pure alpha alumina (1 m2/g). The degree of calcination determines these extremes. High purity aluminas are deagglomerated to the desired particle size and distribution by a variety of noncontaminating methods. Both very narrow and broad distributions are available. These aluminas also are used as submicron polishing powders in fabricating precision optics and preparing metallographic samples. A number of nominal particle sizes are used, the most common span the 0.05 -3 μm (median) range. ALUMINA, HIGH-PURITY SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com MATERION CERAMICS, INC. 6100 S. Tucson Blvd. Tucson, AZ 85706 (520) 746-0251 Fax: (520) 294-8906 Email: [email protected] Website: www.materion.com/ceramics ALUMINA, HYDRATED. Hydrated aluminas (Al2O3-3H2O) are fine white powders manufactured from bauxite by the Bayer process. Major uses are as a flame retardant chemical and as a filler in plastics. ALUMINA, HYDRATED SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com CERAMIC INDUSTRY ³ January 2012

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ALUMINA, HYDRATED SUPPLIERS CONTINUED RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA, REACTIVE. “Reactive alumina” is the term normally given to a relatively high purity and small crystal size (<1 mm) alumina that sinters to a fully dense body at lower temperatures than low-soda, medium-soda or ordinary-soda aluminas. These powders are normally supplied after intensive ball milling, which breaks up the agglomerates produced through calcination. They are used where exceptional strength, wear resistance, temperature resistance, surface finish or chemical inertness are required. Source: AZoM.com (the A to Z of Materials), www.azom.com.

ALUMINA, REACTIVE SUPPLIERS

ALMATIS 501 W. Park Rd. Leetsdale, PA 15056 (800) 643-8771; (412) 630-2800 Fax: (412) 630-2900 Email: [email protected] Website: www.almatis.com

ALUMINA, TABULAR SUPPLIERS CONTINUED ity of clear crystals, together with their high- temperature stability, make them of considerable value for scientific and military apparatus. Current techniques permit production of large-diameter windows. These may be sealed to metals, glass or other ceramic materials. Single crystal, chromium doped Al2O3, called synthetic ruby, is used as the optical pump source of numerous types of lasers. ALUMINA, SINGLE CRYSTAL SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com ALUMINA, SPHERICAL. Spherical alumina has been used to develop fillers with high thermal conductivity for semiconductor sealants, resins and rubbers, as well as applications in grinding grits and spraying materials. (See ALUMINA.) ALUMINA, TABULAR. Tabular aluminas are nearly 100% alpha phase, the conversion being effected by heating the material above 1870°C (3400°F). They typically analyze above 99.5% alumina, and the Na2O content can be made less than 0.20%. Tabular aluminas are recrystallized, sintered alpha-Al2O3 products made using calcined alumina which is produced by the Bayer process. The large, hexagonal, elongated tablet-shaped alpha-Al2O3 crystals (40 to >200 mm median) characterize and give rise to the name “tabular alumina.” ALUMINA, TABULAR SUPPLIERS

ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA, SINGLE CRYSTAL. Al2O3. Mol. wt. 101.9; sp. gr. 3.98 g/ cm3; m.p. 2040°C; hardness Mohs 9; crystal structure hexagonal; thermal expansion at 50°C parallel to c-axis 6.66 x 10-6, perpendicular to c-axis 5.0 x 10-6; electrical resistivity at 500°C 1011 ohmcm.; dielectric constant below 300 MHz ~10.6 parallel to c-axis, 8.6 perpendicular to c-axis; dielectric loss tangent d <0.002 at 1 kHz, <0.0001 at 300 MHz; ultraviolet transmission 20% at 1500 angstroms; infrared transmission 92% at 3 mm, 50% at 6 mm. Occurs naturally as corundum, ruby and sapphire. Corundum is a clear, transparent crystal of relatively high purity; sapphire and ruby owe their color to the presence of impurities in concentrations up to a few percent. Synthetic alumina crystals, both transparent and colored, are produced by the Vemeull or flame-fusion process from finely divided a alumina powder. The latter is usually prepared by the thermal decomposition of purified ammonium alum to which any desired coloring impurities have been added. In addition to their application as jewels, synthetic Al2O3 crystals are widely used in industrial applications requiring high resistance to abrasion, for example as watch bearings, fiber drawing dies, etc. The infrared transmissiv-

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Materials Handbook

ALMATIS 501 W. Park Rd. Leetsdale, PA 15056 (800) 643-8771; (412) 630-2800 Fax: (412) 630-2900 Email: [email protected] Website: www.almatis.com

ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

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RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA, TRANSFORMATION TOUGHENED. (TTA.) M.p. 2050°C; hardness 2100 kg/mm2; strength 900 MPa; CTE 7 x 10-6/°C; thermal conductivity 0.07 cal/cms°C; toughness 8 MPa•m-1/2; average particle size 0.5 μm. Purities up to 99.99% are commercially available. Two explanations—microcrack and induced stress— account for toughening in the alumina zirconia system. The microcrack explanation depends upon the difference in thermal expansions between the alumina matrix and zirconia particles. This difference creates microcracks which dissipate the energy of propagating cracks. A 3-5% volume expansion of the zirconia particles generates the microcracks in the matrix. The induced stress explanation depends upon the tetragonal to monoclinic transformation of ZrO2 below 1200°C. TTA can metastably retain the high-temperature tetragonal phase. The alumina matrix provides a compressive force which maintains the tetragonal phase. Stress energies from propagating cracks cause the martensitic transition of the metastable tetragonal to the stable monoclinic zirconia. The energy used by this transformation (multiplied by the number of transformations) is sufficient to slow or stop propagation of the cracks. There also are proponents of a combination microcrack-induced stress theory. TTA is formed by both dry pressing and slip casting. Most of the characterization work on the material used dry-pressed and sintered samples. Slip casting TTA is a recent development, and it has been shown that single-phase b-Al2O3 and b-Al2O3/ZrO2 composites fabricated in this manner have sintering temperatures of 1480°C and 1535°C, respectively, which are lower than those reported for dry-pressed bodies of the same composition. A typical Al2O3/ZrO2 composite contains 8-15 vol % ZrO2. ALUMINA, TRIHYDRATE. Al2O3 3H2O or Al(OH)3. Normally refers to Bayer process alumina trihydrate (more properly termed aluminum trihydroxide). The product is derived from bauxite by way of the Bayer process and can be sold as a wet filter cake, dried powder or ground product. The unground product has a typical D50 of between 80 and 100 microns and has a light beige or off-white color. Ground products can have particle sizes as fine as about 1 microns. Specialty alumina trihydrates are available with particle sizes below 1 micron or as very white products. Alumina trihydrate is typically used as an alumina source in ceramics, glazes or glasses. Its use in ceramic applications is normally limited to applications where all the alumina will be reacted with other components to form another crystalline phase. The majority of the water (total of about 34% by weight) is lost between 200 and 400°C, but small amounts continue to be lost until nearly 1000°C. It is often used as a flame retardant filler in plastics or as a chemical precursor where alumina is required.

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ALUMINA, TRIHYDRATE

ALUMINA, TRIHYDRATE SUPPLIERS

RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com ALUMINA, ZIRCONIA-TOUGHENED. These materials posses a combination of high strength (from zirconia) and high hardness (from the alumina phase). They have excellent wear resistance, both in sliding and abrasive conditions, and they are more abrasive-resistant than typical tungsten carbide. They are used in applications that require wear resistance, corrosion resistance, high temperature stability and superior mechanical strength, such as pump components, battery tooling, metal forming components, bushings and other industrial components. ALUMINUM. Metal available in various alloys and in sheet, foil, extrusions and castings for porcelain enameling with a variety of P/E compositions suitable for indoor and outdoor applications. Special enameling grades of aluminum had to be developed because porcelain enameling temperatures are higher than the annealing temperatures of con-

ventional nonheat-treatable aluminum alloys. Proper matching of aluminum alloy sheet thickness with forming, firing and service conditions is most important to avoid rejects due to warping, sagging and hairlining. Large flat areas of sheet tend to warp when fired but can be rolled flat. Deep-drawn parts pose special problems for the porcelain enameler because they usually require use of nonheat-treatable alloys. Aluminum extrusions for porcelain enameling must be designed with care, avoiding thin walls. Corners, inside and out, must have minimum radii of 1/16 in. to prevent burn-off of the P/E coating and buildup on internal areas. Thorough cleaning (pretreatment) of aluminum is essential to assure uniform, tightly adherent P/E coatings. Two general types of cleaners are used: surface reactive and nonreactive solutions. Surface reactive solutions actually remove the Al2O3 layer on the alloy’s surface and replace it with another oxide or coating of uniform character and thickness. Nonreactive cleaners remove soil by soap emulsifying or solvent action. Examples include nonetching aluminum cleaners, and vapor and solvent degreasing. Most proprietary cleaners are used in concentrations of 4-8 oz/gal at temperatures of 140-160°F with immersion times of 3-8 min. In any event, use of a deoxidizer is recommended. A typical solution: 23 oz/gal commercial grade H2SO4 and 5 oz/ gal technical grade chromic acid. Immerse parts for 3-5 min at a solution temperature of 150-160°F. Numerous pretreatments for aluminum are commercially available. Frit manufacturers, however, may recommend a particular pretreatment.

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ALUMINUM HYDROXIDE

ALUMINUM CARBIDE. Al4C3. Mol. wt. 143.88; m.p. 2800°C; density, 2.99 g/cm3. Yellow-green with hexagonal crystal structure, it decomposes in dilute acid and decomposes to produce CH4 in cold water. The material is stable up to 1400°C. ALUMINUM CARBIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com ALUMINUM HYDROXIDE. Al2O3xH2O. Loses water at 300ºC (572ºF); sp. gr. about 2.4. Aluminum hydroxide is a white gelatinous precipitate used in the manufacture of glassware and glazes.

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ALUMINUM HYDROXIDE

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ALUMINUM NITRIDE

ALUMINUM HYDROXIDE SUPPLIERS RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com

Materials Handbook

ALUMINUM NITRIDE. AlN. Mol. wt. 40.99; density 3.26 g/cm3; CTE 4.6 x 10-6/°C; m.p. 2200°C under 4 atm. N2, sublimes at 1 atm. White, hexagonal crystal structure. Powder hydrolyzes on contact with water or water vapor. Water-resistant powders that allow aqueous processing are commercially available. Stable against acids, slightly reacts with bases. Made by reacting aluminum metal with nitrogen, by reduction of aluminum oxide with carbon in the presence of nitrogen or ammonia, or by decomposition of the product of reaction between aluminum trichloride and

ammonia. Powder may be sintered to full density above 1800 in 1 atm. N2 with the addition of sintering aids such as Y2O3 or CaO. Thermal conductivity in excess of 200 W/ mK can be achieved in sintered parts, which is five times that of aluminum oxide. Dielectric strength is 1.5 times, and electrical resistivity and mechanical strength are comparable to that of aluminum oxide. Dielectric constant is about half that of aluminum oxide. Major applications include thermally conductive substrates and heat sinks for semiconductors, automotive and transit power modules, mobile communications and multichip modules. ALUMINUM NITRIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

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CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com

Refractory Metals | Advanced Ceramics

Advanced Ceramic Powders Advanced Material Specialists, Inc.

H.C. Starck produces a full range of Advanced Ceramic Powders, from Aluminum Boride to Zirconium Nitride. Besides standard grades, H.C. Starck can also provide powders to individual customer requirements. MAIN PRODUCTS NITRIDES

CARBIDES BORIDES

TYPICAL APPLICATIONS

Aluminum Nitride (AlN) > Substrates, Heat Sinks, Filler for Polymers Boron Nitride (BN) > High Temperature Lubricants, c-BN Precursors, Filler, Evaporation Boats Silicon Nitride (Si3N4) > Wear Parts, Ball Bearings, Cutting Tools, Si Ingot Production (PV) Boron Carbide (B4C) > Additive, Light Weight Armor Silicon Carbide (β-SiC) > Sliding Bearings, Seal Rings, Wear Parts Lanthanum Hexaboride (LaB₆) > Cathodes for Plasma Technique, Filler Titanium Diboride (TiB2) > Evaporation Boats, MMCs, Crucibles, Armor Zirconium Diboride (ZrB2) > Ultra High Temperature Ceramics (UHTC), Additive

SILICIDES Molybdenum Disilicide (MoSi2) > Ceramic Composites, Heating Elements BORON

Amorphous + Crystalline (B) > Neutron Absorbers, Ingniter in Airbags, Additive, Pyrotechnics, Metallurgy

OXIDES North America Robert Jensen T +1.617.630.5818 F +1.617.630.5919 [email protected]

HAI ADVANCED MATERIAL SPECIALISTS INC. 1688 Sierra Madre Cir. Placentia, CA 92870 (877) 411-8971 Fax: (877) 411-8778 Email: [email protected] Website: www.haiams.com H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

Yttrium Oxide (Y2O3) > Additive, Structural Ceramics Europe Bettina Essmann T +49 5321 751-3145 F +49 5321 751-4145 [email protected]

Asia David Dai T +86 21-6090-5255 Ext. 264 F +86 21-6090-5256 [email protected]

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ALUMINUM OXIDE

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ANTIMONY OXIDE

ALUMINUM PHOSPHATE, MONO BASIC SUPPLIERS CONTINUED ALUMINUM OXIDE. (Corundum.) Al2O3. (See ALUMINA.) ALUMINUM OXIDE SUPPLIERS

ALMATIS 501 W. Park Rd. Leetsdale, PA 15056 (800) 643-8771; (412) 630-2800 Fax: (412) 630-2900 Email: [email protected] Website: www.almatis.com

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CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com ALUMINUM PHOSPHATE, MONO BASIC. (Mono Aluminum Phosphate.) Al(H2PO4)3. Mol. Wt. 317.94. Mono aluminum phosphate (MAP) is commercially available as an opaque sequestered solution for refractory bonding. It decomposes to orthophosphate above 400ºF. Buffered mono aluminum phosphate is the primary bond phase in refractory plastics and ramming mixes. In general, this product is added so that the P2O5 content in the final mix is 4%. The 15-20% plastic portion should be kaolin augmented with a small amount of western bentonite. The balance should be graded refractory aggregate. MAP is also available as a dry water-soluble powder. Dry MAP is used as a cement accelerator/modifier or with a source of base like MgO to form rapidly setting cements. Dry MAP can also be used where a dry source of P2O5 is required. ALUMINUM PHOSPHATE, MONO BASIC SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com

REFRACTORY MINERALS CO. INC. 150 S. Jennersville Rd. West Grove, PA 19390 (610) 869-3031 Fax: (610) 869-9805 Email: [email protected] Website: www.phosphatebonds.com ALUMINUM SILICATE. (See ANDALUSITE.) ALUMINUM SILICATE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com ALUMINUM TITANATE. Al2O3-TiO2. Stable from 1260-1865°C, while instability from 860-1260°C is reduced by minor amounts of iron or magnesium titanate. Made by reacting Al2O3 and TiO2 for 12 hr at 1300°C. CTEs along the three major crystal axes: (a) 8.3 x 10-6/C; (b) 18.7 and (c) 2.8. CTE of the aggregate (25-1000°C) decreases with increasing temperature, reaching -2 x 10-7/C after aging at 16501700°C. Aluminum titanate shows an expansion hysteresis loop due to internal fractures caused by anisotropy of the expansion coefficients. Fired aluminum titanate is easy to machine. This characteristic, combined with extremely high heat resistance, makes it an attractive candidate for such thermal shock-resistant applications as catalytic converter and diesel engine components. ANDALUSITE. Al2O3SiO2. (Aluminum silicate.) Sp. gr. 3.0-3.2; hardness Mohs 7.0-7.5. This member of the trimorphic series, together with sillimanite and kyanite, has a theoretical composition of 62.9% Al2O3 and 37.1% SiO2. Crystallizes in prismatic orthorhombic crystals; gray, greenish, reddish or bluish in color; transparent to opaque. Occurs commonly as a product of contact metamorphism in slates and schists. Its name is derived from the Andalusia province of Spain, the first locality in which it was noted. Until 1955, the only deposit mined in the United States was in the White Mountains near Laws, Calif. The andalusite was used in making spark plug porcelain. This mine has since closed. However, another deposit at Hillsborough, N.C., has been mined continuously since 1961. The North Carolina mineral occurs as bluish to grayish crystals averaging 1/8-1/4 in. square with a small amount of pyrophyllite in a groundmass of sheared, fine-grained quartzite. Diaspore and topaz occur sporadically in minor amounts. The North Carolina operation does not produce a pure andalusite concentrate, but instead offers a controlled blend of andalusite, pyrophyllite and silica to the refractory and whiteware segments of the ceramic market. In these products, andalusite makes up about 40% of the total. Andalusite also is mined in South Africa, the former USSR, France and Spain. South African deposits account for more than 80% of production outside the former USSR. The ore bodies generally contain less than 10% andalusite. Saleable concentrates consist of distinct, nearly cubic crystals. Typically, crystals are no larger than 0.25 in. The highest grade andalusite commercially available comes from the western region of the Transvaal province of South Africa. Its bulk density is 3.10 g/cm3. Andalusite is widely used in refractories, both brick and monolithics. Along with sillimanite and kyanite, it has

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become an important mullite-forming raw material in acid refractories. It dissociates into mullite and free silica at 1400°C (2550°F), and the resultant mullite is stable up to 1810°C (3300°F). It is the formation of this mullite that accounts for its high refractoriness with a PCE of 36-37. Andalusite undergoes only a small volume increase (about 4%) during mullitization. Therefore, calcination is unnecessary prior to use in refractory brick and other products. In practice, andalusite expands about 1.5% when fired up to 1500°C. By comparison, kyanite converts to mullite at 1500°C (2730°F) with a large volume increase (1618%) and is, therefore, usually calcined before use. Andalusite refractories are used mainly in the iron and steel industry in blast furnace troughs and stove checkers, iron and steel pouring ladles, and electric furnace roofs. In addition, andalusite is used for kiln furniture (cordierite), glass tank regenerators and, in the aluminum industry, anode baking furnaces. A refined, high-grade andalusite is an excellent alumina source for frits for ceramic glazes. ANDALUSITE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com ANTIMONY OXIDE. Sb2O3. Mol. wt. 291.52; sp. gr. 5.2-5.7; very slightly soluble in water. Derived principally from stibnite, which is mined in western United States, China, Mexico and Bolivia. The oxide also is produced by the oxidation of antimony metal or as a byproduct in the refining of antimonial-lead alloys. Antimony oxide’s most important ceramic industry application is in the porcelain enameling industry, where it is used as an opacifier, both in the raw batch and in combination with other oxides as a mill addition opacifier. It also is often added as sodium antimonate. Antimony finds its chief use in leadless cast iron enamels and a few colored sheet steel enamels. Its opacifying efficiency in these types of enamels has been markedly increased over the years. When used in lead-bearing enamels, a yellow color may be produced by the formation of lead antimonate. Also, antimony oxide does not give as good opacity in lead-bearing enamels as it does in the leadless types. Since the development of titania white enamels, the importance of antimony or sodium antimonate as a P/E opacifier for sheet steel has been greatly reduced. Nevertheless, there are still numerous applications where antimonybased white enamels cannot be replaced by titania enamels. Antimony-bearing, light-colored ground coat enamels are, however, still of importance where cobalt-nickel ground coats have to be replaced. The formation of lead antimonate, referred to above, is sometimes deliberately encouraged in low-temperature pottery glazes, where a compound of lead oxide and antimony oxide, known as Naples yellow, is used. Antimony is not often used as an opacifier in glazes, but is used in the pottery industry as a yellow body stain, usually in combination with rutile or titanium dioxide. Antimony oxide, when applied to red-burning clay, will chemically bleach the clay surface to a buff color. The brick industry uses this techinque to produce interesting colors. Application is by spraying in a water or oil suspension. In glasses, antimony is used as a decolorizing and fining agent. The decolorizing action appears to be the result of oxidation of the iron to its ferric state by the action of pentavalent antimony. To ensure the development of pentavalent antimony, for either decolorizing or fining, an oxidizing agent—usually sodium nitrate—is commonly used together CERAMIC INDUSTRY ³ January 2012

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ANTIMONY OXIDE

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BARIUM CARBONATE

with the antimony oxide. Antimony has a special advantage in that glasses decolorized with it do not change color upon solarization as do glasses decolorized with arsenic oxide. It has a substantially lower vapor pressure than arsenic oxide and is less subject to volatilization losses in the early stages of melting. Antimony oxide is important as a fining agent, especially in optical glass batches and in ruby red compositions. Antimony trioxide, without an accompanying oxidizing agent, is used for the stabilization of emerald green glass, in which case it is a glass former and very soluble. ANTIMONY SULFIDE. Sb2S3. Mol. wt. 339.7; sp. gr. 4.6. Black needlelike crystals, somewhat soluble in water. Commonly called “black needle antimony.” The standard commercial grade contains a minimum of 70% metallic antimony. It is sometimes used in glass batches for obtaining a cloudy amber or ruby glass. In the production of opal glass, it is occasionally used in small amounts to assist the action of opacifying agents. Normally, however, the antimony desired in ceramic compositions is gained by use of antimony oxide, which does not introduce any sulfur. Antimony sulfide also may be used in enamel batches, although the oxide is used to some extent in the hollowware industry in the production of mottled gray enamels. Based on experience gained in hollowware enameling, a trend is developing in the application of single-coat (titania) white directly on steel. By simultaneously introducing sulfur and antimony in the form of antimony sulfide, adherence of white enamel to steel is said to be enhanced. ANTIMONY SULFIDE, HIGH-PURITY. Antimony sulfide with purity levels of 98-99.99%. (See ANTIMONY SULFIDE.) ARSENIC OXIDE. As2O3 (arsenious acid, white arsenic). Mol. wt. 198; sp. gr. 3.9; sublimes at 193°C; soluble. White poisonous powder derived from the roasting of arsenopyrite (mispickel), FeAsS. It is obtainable as “dense arsenic,” which is processed so that the crystals are relatively large and free from annoying dust. “Glassy arsenic,” a vitreous form of the trioxide made by heating under pressure, is a popular reagent in German glass practice. Lumps of it may be thrown into a pot of molten glass to sink and vaporize, thereby sweeping out fine bubbles. As a fining agent, arsenic is used in the presence of niter, which favors the oxidation of As2O3 and its compounds in the early stage of the melt. The decomposition of these compounds during the high-temperature fining stage provides the necessary oxygen. In tank glass, arsenic is used as one of the decolorizing agents, a function it serves because of the oxidizing effect of the pentavalent As2O3 on the ferrous ion. Glasses decolorized with selenium and cobalt, however, will tend to be colored yellow or dark gray if not carefully controlled. Toward manganese, however, arsenic acts as a reducing agent, and the purple color of manganese glasses fades to the faint color of the manganous ion in its presence. This fading is accentuated by the application of heat in glazing, annealing and other glass processing operations. Arsenic oxide is largely responsible for glasses changing color or fading when exposed to sunlight. If rare-earth decolorizers, which usually contain cerium oxide, are used, even trace amounts of arsenic must be avoided or brownish discoloring occurs. Arsenic oxide usually adds to the stability of color in tank glasses, increasing brilliancy and making colorless glass easier to produce. When used in light-green tank glass, it prevents the color from becoming blue-green, because of its oxidizing effect on iron. In pot glasses, large quantities of arsenic oxide often are used. It is said to help in fining and reducing yellow coloration. Arsenic oxide is used as an opacifier in glazes, though it does not ordinarily give as satisfactory results as tin oxide.

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In enamels, the toxicity of arsenic oxide limits its use to special products, such as jewelry enamels, which are crucible-melted in small batches.

B

ADDELEYITE. Zirkite. Mol. wt. 123; density 5.56 g/ cm3. Essentially a mineralogical composite of natural zirconium oxide, hydrated zirconium oxide and zirconium silicate. Composition range for various grades: 65-75% ZrO 2, 10-14% SiO2, 3-5% other materials. Although its uncertain purity limits applications, baddeleyite makes both an excellent refractory and an ingredient for low-expansion bodies. BALL CLAY. (See CLAY, BALL.) BARITE. (See BARYTES.) BARIUM ALUMINATE. 3BaO-Al2O3. Recommended for use in glass batches as the source of BaO in the finished product. Specific compositions are used for cathode coatings in vacuum tubes. For data on effects of BaO in glass, see BARIUM CARBONATE, BARYTES.

BARIUM CARBONATE. BaCO3. Mol. wt. 197.4; sp. gr. 4.4; m.p. 1360°C. Insoluble in water but soluble in acids. Toxic. Occurs as the mineral witherite, which is mined in England and California. The precipitated barium carbonate used in ceramics is obtained from barytes (barite, BaSO4), which is reduced to soluble barium sulfide (black ash) and converted to the carbonate by precipitation with soda ash. Barium compounds have been used in the manufacture of optical glass for many years, with some of these special compositions containing as much as 30% BaO. Barium also has come into general use for certain less-expensive glassware, and is found in amounts of about 0.5% in some bottle and flat glass compositions. The television tube industry is another large consumer of barium glasses. The properties imparted, in most cases, are similar to those given to glass by calcia or magnesia. Barium carbonate decreases the solubility, though not to the same extent as lime. Barium glasses tend to be denser, and more brilliant than lime glasses but less dense and less brilliant than lead glasses. Barium glasses are less durable than the corresponding lime glasses but more durable than the corresponding lead glasses. Other properties fall between those of the lime and lead types. The one advantage which barium has is the fact that it is not reduced by furnace gases; in other words, barium glasses may be melted in tanks and open pots without discoloration. In pressed tableware, barium glasses are helpful because the barium imparts a greater brilliance to the product than lime, and it is superior to lead because the fire polish on a barium glass after pressing gives a brilliant finish. Barium decreases the specific heat, elasticity and toughness when it replaces lime. When barium replaces dolomitic lime in weight percentage, chemical durability decreases; softening temperature drops; coefficient of linear thermal expansion rises; density increases, almost as a linear function; modulus of elasticity appears to decrease slightly; index of refraction falls very slightly; melting time decreases; and working properties improve. A typical composition range for pressed tableware batches: Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000 lb Potash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-150 lb Soda ash . . . . . . . . . . . . . . . . . . . . . . . . . . . 150-300 lb Barium carbonate . . . . . . . . . . . . . . . . . . . . 100-250 lb Nitre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-60 lb Lime feldspar . . . . . . . . . . . . . . . . . . . . . . . . 50-100 lb Barium is used in heat-resistant ware and is an important ingredient in many crown and flint optical glasses. Barium glasses have a strong corrosive action on glass

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Materials Handbook

refractories and for this reason a special type of glass pot is used for making barium crown glasses. Special optical glasses contain up to 20% or 30% barium oxide. This is to obtain certain desired optical properties rather than to improve workability, as glasses high in barium oxide are freed from seed with difficulty, and they attack refractories vigorously. They also are difficult to press as the softening point is high, and they set very quickly. In enamels, barium carbonate acts as a flux and has the lowest melting point of all the alkaline earths. It is superior to calcium carbonate and is considerably less expensive than red lead or zinc oxide. Though seldom used in excess of 10% of batch weight for sheet steel enamels, barium carbonate improves glass and mechanical strength, elasticity and resistance to organic acids. Barium carbonate has a melting point of 1350°C, yet it reacts with silica in the enamel batch at 700°C. The formation of barium orthosilicate and metasilicate occurs at temperatures as low as 900°C. If soda is present, these reactions may begin as early as 400°C. Barium is not sensitive to the products of combustion or to cast iron high in carbon, while lead and zinc oxides are reduced in their presence. In sheet iron enamels low in alkalies, the barium carbonate content should not exceed about 7%, but high-borax enamels allow a greater addition. Barium carbonate does not function satisfactorily in enamels containing certain forms of antimony because sulfur, usually present as an impurity in the antimony, reacts with the barium to form barium sulfate which gives a puckery effect to the finish. When sodium antimonate is used as the source of antimony, however, this defect is not noted. In leadless cast iron enamels, barium is an active flux and amounts up to 12% can be used in sanitaryware cast iron enamels. It aids in giving a better luster and harder surface to the finish. Barium carbonate prevents formation of scum and efflorescence in brick, tile, masonry cement, terra cotta and sewer pipe by insolubilizing the soluble sulfates as barium sulfate. Thus, many clays otherwise unsuitable can be used. It diminishes porosity, prevents discoloration. The ability of barium carbonate to insolubilize sulfates puts it in common use to control casting slip properties in the whitewares industries. Its use can help control casting rates and prevent “flabby” cast. In fired ware made of steatites, forsterites, zircon porcelains, titanates, etc., BaCO3 is used to reduce dielectric loss. (Fed. Spec. JAN-1-10) Barium carbonate produces maximum flux density in hard-core permanent magnets. Fine particle size is needed for intimate mix and denser magnets. About 18% BaCO3 is used in a typical barium ferrite mix. BaCO3 also is used to make barium titanates for electronic applications. Barium titanates have high dielectric constants and good piezoelectric and ferroelectric properties. In pottery bodies, barium carbonate seems to impart better translucency, but bodies containing any appreciable amount have only a slight range of vitrification and are apt to be weak, of poor color and subject to excessive shrinkage. In most whiteware bodies, barium causes blistering. Barium carbonate also is used in glazes as a flux or to assist in the formation of a matte structure. Barium forms silicates slowly, but when barium is completely combined, it becomes almost as active a fluxing agent as lead oxide. When used in glazes in amounts greater than 0.1 equivalent, it renders the glaze too refractory for satisfactory commercial firing.

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2012 Edition

BARIUM CARBONATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com LIGNOTECH USA INC. 100 Grand Ave. Rothschild, WI 54474 (715) 355-3603; (908) 612-0948 Fax: (715) 355-3648 Email: [email protected] Website: www.lignotech.com BARIUM CHLORIDE. BaCl2-2H2O. A water soluble, white crystalline material used to set up porcelain enamels for sheet steel. Addition of 5-10 g barium chloride per 100 lb of ground-coat frit milled with high-sulfate water will increase and stabilize the set. When used for this purpose, the barium chloride should be added to the mill batch before adding the water. BARIUM FLUORIDE. BaF2. Mol. wt. 175.4; sp. gr. 4.83; m.p. 1280°C. White-colored material often used in enamel frits where it acts both as a flux and an opacifier. BARIUM FLUORIDE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com BARIUM HYDROXIDE. White powder or crystals, with the chemical formula Ba(OH)2. Soluble in water, alcohol and ether. The most common forms are octahydrate—Ba(OH)2 x 8H2O—and monohydrate—Ba(OH)2 x H2O. Barium hydroxide is used in the manufacture of polyvinylchloride stabilizers, lubricant additives and barium soaps. It is used as a water treatment, as a catalyst in the glass industry and as a sulfate-controlling agent in ceramics. BARIUM HYDROXIDE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com BARIUM METAPHOSPHATE. Ba(PO3)2. Used in conjunction with gray NiO (See NICKEL OXIDE) to control primary boiling during firing ceramic coatings on steel. The important properties of Ba(PO3)2 for the precoat treatment are its low melting point (1560°F) and high solubility for iron oxide.

BARIUM CARBONATE

BARIUM METAPHOSPHATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com BARIUM NITRATE. Ba(NO3)2. Although more expensive than barium carbonate, this material has been used in small amounts in certain barium optical glasses when nitrates of sodium or potassium could not be employed. It also has been used in enamels to replace alkali nitrates. Barium nitrate is said to give better homogeneity and opacification. Being a weaker base, it attacks melting vessels much less than the carbonate. BARIUM NITRATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com BARIUM OXIDE. BaO. Mol. wt. 153.36; m.p. 1923°C; density 5.72 g/cm3. Cubic or hexagonal crystals are white to yellowish in color, and soluble in water and dilute acids. BARIUM PEROXIDE. BaO2. Sp. gr. 4.58; m.p. 1470°F. Light grayish tan powder used in very limited quantities in the glass industry. BARIUM TITANATE. BaTiO3. M.p. >1500°C. Pure form undergoes abrupt phase change from tetragonal to cubic at 130°C, the Curie temperature. Barium titanate is usually produced by the solid-state reaction of barium carbonate and titanium dioxide. Has widespread use in the electronics industry because of its high dielectric constant, and piezoelectric and ferroelectric properties. The high dielectric constant of BaTiO3 and the ease with which its electrical properties can be modified by combination with other materials make it exceptionally suitable for miniature capacitors. The dielectric constant of barium titanate ranges from 1200-1600 at 1 kHz and 25°C, increasing to ~10,000 as the Curie temperature is approached. Under these same conditions, the power factor is a maximum of 1.5%. Because of the large variation of its dielectric properties with temperature and voltage, barium titanate is not, except in rare instances, used as a dielectric without modification. Dielectric properties can be easily modified, however, by combination with zirconates, stannates and other titanates, for example, to form solid solutions, defect structures or mixtures. Modified barium titanates can be produced with a wide variation in dielectric properties— from those which are comparatively insensitive to voltage and temperature and have a low dissipation factor, to those which show a significant variation with temperature and voltage and have a high dissipation factor. Dielectric and piezoelectric properties of BaTiO3 can be affected by stoichiometry, microstructure and additive ions that can enter into solid solution. With excess Ba+2, generally a fine textured matrix with <5 μm grain is obtained. With excess Ti+4, grain growth is rather extreme, and at comparable firing temperatures, results in coarse grains of 50-100 μm. Nonstoichiometry originating from the BaO:TiO2 ratio or additional impurities may result in semiconductive ceramics upon firing. The transition temperature of barium titanate can be shifted and depressed. Sr+2, Zr+4, Sn+4 and Hf+4 may shift it downward to room temperature and below. Bi+3 and

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BASTNASITE

Pb+2 substitution may result in a shift to higher temperatures. Dielectric permittivity of barium titanate at room temperature is usually claimed to be ~2000 which may vary from ~1500-3500, depending upon purity and microstructure. Barium titanate PTC ceramics have been shown to exhibit twin lamellae lying on the {111} plane in crystallites. This condition is necessary for anomalous grain growth. Since anything that will affect the crystal lattice of barium titanate will alter its dielectric properties, it is important that impurities (SiO2, Al2O3, etc.) be controlled and maintained at comparatively low levels, not only in the asreceived material but also throughout subsequent processing operations. Barium titanate is produced by solid-state reaction of BaCO3 + TiO2 or precipitation from an intermediate such as the oxalate. There are three basic steps involved in preparing barium titanate bodies for capacitors and other dielectric applications: preparation of the dielectric composition (usually involves mixing, sometimes calcination and milling); forming of the dielectric unit (pressing, extrusion, punching or, in the case of multilayer capacitors, tape casting); and thermal treatment and densification. Depending on the composition, barium titanate bodies can be fired to vitrification at temperatures between 1900 and 2600°F. The multilayer ceramic capacitor process, which is the most popular method of making monolithic capacitors, may include mixing of powder with organic binder in water or a solvent-based system, tape casting (thickness: ~l25 mm), silk screening of electrode, stacking of tape, cutting of laminated tape into individual capacitors, binder burn-out, firing, termination and encapsulation. Barium titanate ceramic products are used for applications in underwater sonar, guided missiles, acoustic mines, ultrasonic cleaning, measuring instruments (flaw detection, liquid level sensing, thickness gauges), accelerometers, sound reproduction, filters, ultrasonic therapy, ultrasonic machining and vibration detection and, most important, for ceramic capacitors of disk, tube and multilayer designs. Multilayer capacitors are the single highest user of barium titanate. BARIUM ZIRCONIUM SILICATE. BaZrSi3O9. Used in the manufacture of refractory shapes and molds. Its luminescence also makes it suitable for the production of items such as high-pressure mercury vapor discharge lamps. BARYTES. BaSO4. (See BARIUM CARBONATE.) BASTNASITE. (Ce, La, Y)CO3F. Sp. gr. 4.7-5.0; hardness 4-4.5 mohs. Typically pale white, tan, gray, brown, yellow or pink in color, bastnasite is one of a few rare earth carbonate minerals. It contains cerium, lanthanum and yttrium in its generalized formula but is officially divided into three minerals based on the predominant rare earth element: bastnasite-(Ce), with a more accurate formula of (Ce, La) CO3F; bastnasite-(La), with a formula of (La, Ce)CO3F; and bastnasite-(Y), with a formula of (Y, Ce)CO3F. There is little difference in the three in terms of physical properties, and most bastnasite is bastnasite-(Ce). Cerium in most natural bastnasites usually dominates the others. Bastnasite is closely related to the mineral parisite and forms a series with the mineral hydroxylbasnasite. The structure of bastnasite is made up of stacks of carbonate ion layers and CeF layers. The CeF layers form flat hexagonal sheets with each cerium bonded to three fluorines. The carbonate layers are more complex with angled carbonate triangular groups. The structure is closely studied because it is one of the few rare earth mineral structures that can accommodate variously sized cations. Bastnasite gets its name from its type locality, Bastnas Mine, Riddarhyttan, Vastmanland, Sweden. Although it is never found in great concentrations, it is widespread and is one of the more common rare earth carbonates. Bastnasite CERAMIC INDUSTRY ³ January 2012

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BASTNASITE

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BERYLLIUM OXIDE

has been found in karst bauxite deposits in Hungary, Greece and the Balkans. It has also been found in carbonatites, a rare carbonate igneous intrusive rock, at Fen, Norway; Bayan Obo, Mongolia; Kangankunde, Malawi; Kizilcaoren, Turkey and Mountain Pass, Calif. At Mountain Pass, bastnasite is the leading ore mineral. Some bastnasite has been found in the unusual granites of the langesundsfjord area in Norway; Kola Peninsula; Mont Saint-Hilaire mines, Ontario, Canada; and Thor Lake deposits, Northwest Territories, Canada. Hydrothermal sources have also been reported. The major end use of bastnasite is glass polishing because it offers a low-cost way to obtain the necessary cerium used in the polishing compounds. Bastnasite is also used in television faceplates and light bulbs for ultraviolet shielding and de-coloring. BAUXITE. Generally nonplastic but with variable physical characteristics, a mineral raw material used to produce the alumina from which aluminum metal is made, as well as alumina-based aluminum oxide for ceramic and chemical applications; Major domestic deposits are in Arkansas. Physical properties of bauxites vary widely, depending on type, nature of deposit and tectonic history. In texture, some bauxites are soft, friable and structureless; some are hard, dense and pisolitic; still others are porous but strong, or are stratified. Color may be pink, cream, red, brown, yellow or gray, depending upon the amount of impurities, particularly iron oxide. The alumina constitutents in the various types of bauxite have been identified as gibbsite (trihydrate), boehmite and diaspore (monohydrates), alone or in mixtures. The clay minerals kaolinite, hermatite, magnetite, geothite, siderite and quartz may be present as common impurities. Residual minerals may include rutile, anatase and zircon. The specific gravity of bauxite varies, with type and composition, from 2.45-3.25. Bauxites fuse at 1800°C or higher. Trihydrate bauxites start to lose combined water at about 500°C. Any boehmite present will lose water at about 500°C. Combined water is driven off in two main stages: trihydrate converts at about 250°C to monohydrate with loss of 2 moles of water, and most of the remainder is driven off around 550°C. Practical dehydration is attained at about 950°C. The amounts of silica, iron and alkalies present in bauxite control its value for use in refractories, abrasives and cements. Bauxite is an excellent material for refractories provided adequate attention is given to initial calcining to take care of the tendency of bauxite with residual moisture to shrink at the temperatures at which the refractories are used. Bauxite refractories have adequate strength when cold and at working temperatures. They resist cracking, spalling, and chemical and physical reaction with furnace charges. Mullite refractory raw material is produced by the sinterbonded method from mixtures of bauxite and silica sand or quartz, and by the electrically fused-cast method from bauxite-derived alumina. The chief uses of bauxite-containing refractories are: linings in rotary kilns for the manufacture of Portland cement, dolomite and lime; combustion chamber linings for boilers; in the ceramic industry as glass tank blocks, furnace parts, regenerator walls and checkers; in the steel ladles metals industry for center walls of zinc distillation furnaces, bottoms of malleable iron furnaces, water-cooled ports of basic openhearth furnaces, walls and floors of aluminum holding furnaces and in other types of furnaces where the ash is highly corrosive to brick. Bauxite has been used in increasing quantities for the manufacture of special quick-hardening high-alumina cements. These cements are prepared in blast furnaces, rotary kilns or electric furnaces by the fusion of bauxite and limestone. The resulting product consists of a mixture of calcium aluminates and calcium-aluminum silicates with some iron oxide and possibly some calcium silicates.

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Materials Handbook

Bauxite abrasives are prepared by fusion of a mixture of calcined bauxite, coke and iron turnings in an electric arc furnace at temperatures above 2000°F. Massive corundum crystals containing 94-95% aluminum oxide result. These are crushed, ground and separated into various grit or grain sizes, which are then manufactured into such products as grinding wheels, abrasive stones, abrasive cloths and papers, and grinding and polishing powders. The fused alumina grinding wheels used extensively in the metals industries are made of this material. BAUXITE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com BAUXITE, CALCINED. Used for producing abrasives, refractories and other ceramic materials. For refractory purposes a calcined bauxite of high alumina content, controlled low iron and low loss on ignition is required, with low alkali preferred. (See BAUXITE.) BENTONITE. A natural clay-like substance—a hydrous silicate of alumina—derived from volcanic ash with the clay mineral montmorillonite (Al2O3-5SiO2-7H2O) as the chief constituent. Montmorillonite is a trilayered clay, or smectite material. All clays comprising chiefly montmorillonite which have been derived from volcanic ash are classed as bentonites. For practical purposes it is necessary to subdivide bentonite into two types: (1) those that swell enormously when wetted and (2) those that swell no more than other plastic clays. Domestic sources of bentonite include Wyoming and South Dakota. A white bentonite which fires to a light cream color is mined and processed in Texas and also imported from Italy. White bentonites are of interest where color effect on electrical properties must be considered. Treated or refined products having greater plasticizing properties also are available at higher prices. One type consists chiefly of organophyllic (solvent dispersing) clays. During refinement their ions are exchanged for amines, which makes them inert in water-based systems. Another refined product is an air-classified, high-purity montmorillonite with a 20 μm average dry particle size. It is widely used as a glaze suspension agent and plasticizer. Bentonite is variable in its outward appearance and superficial properties. Crude bentonites can be pale buff, green and blue-green, but gray, dull blue and pink also are found. The usual commercial product is cream color, firing to a buff or light red, and may discolor whiteware if more than 2-2.5% is used. Black Hills bentonite (type 1) softens at 1900°F with complete fusion at about 2440°F. A sample analysis of the moisture-free bentonite: Silica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64.32% Alumina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20.70% Iron oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.49% Lime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.46% Magnesia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.26% Potash and soda . . . . . . . . . . . . . . . . . . . . . . . . .2.90% Titania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.11% Sulfur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.35% Chemically held water . . . . . . . . . . . . . . . . . . . . .5.15% Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99.78% Type 1 bentonite is used as a plasticizer in electrical porcelain bodies where it increases dry and fired strengths and reduces absorption. A 2.5% bentonite addition improves plasticity more than a comparable 10% ball clay addition. Bentonite also lowers the PCE of whiteware mixtures,

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although it increases drying and firing shrinkages somewhat. From 1-3% bentonite is used successfully in high temperature cements, mortars and plastic refractories. In porcelain enamels, bentonite is used as a suspending agent. The amount commonly used is 6 oz/100 lb frit, cutting down on the amount of clay needed, although some clay is generally used in conjunction with bentonite additions. Bentonite also gives the dried P/E bisque coating a greater film strength; thus it is a factor in eliminating tearing difficulties and reducing damage done during handling and brushing operations. Natural bentonite contains about 0.75% impurities and, if used in this form, may cause black specking, blisters or pinholes. Purified grades from which the grit has been removed are available, and these grades give best results and enjoy widest commercial use. Settling can be overcome in 90 parts frit-10 parts clay glaze mixtures by adding 0.50% borax, 0.25% magnesium carbonate and 2 oz bentonite (or a small amount of Setit-A) to the mill. If the glaze is in granular form, it is best to grind the glaze for several hours, then add the bentonite and grind for an additional 6 hours. Grinding time, however, can be adjusted to plant practices. Type 2 bentonites are widely used as a clarifying clay, a carrier and sticking agent for insecticides, and for workability in noncolor-critical ware such as sewer pipe and other structural clay products. BENTONITE SUPPLIERS AMERICAN COLLOID CO., INDUSTRIAL SPECIALTIES DIV. 2870 Forbs Ave. Hoffman Estates, IL 60192 (847) 476-0769 Fax: (847) 851-1396 Email: [email protected] Website: www.colloid.com/isg/ SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com BERYL. 3BeO-Al2O3. A mineral consisting of a silicate of beryllium and aluminum that occurs in colorless hexagonal prisms when pure and in various colors (green, blue, yellow or pink) when not pure. Valued as a source of gems, beryl is the principal source of beryllium. Source: www.m-w.com.

BERYLLIA. (See BERRYLLIUM OXIDE.) BERYLLIA SUPPLIERS MATERION CERAMICS, INC. 6100 S. Tucson Blvd. Tucson, AZ 85706 (520) 746-0251 Fax: (520) 294-8906 Email: [email protected] Website: www.materion.com/ceramics BERYLLIUM OXIDE. BeO. (Beryllia.) M.p. 2650°C; density 3.03 g/cm3. Beryllium compounds are toxic and should be used only under the guidance of the supplier and according to local, state and federal regulations. Impervious beryllia ceramics are now almost exclusively of 99.4% purity with higher purity material (up to 99.9% BeO) used to satisfy special requirements. Lower purity is rarely considered because thermal conductivity drops appreciably as the impurity level rises. BeO powder is available in three particle size ranges: (1) Supplier listings indicate paid advertising.

2012 Edition

submicron to 1-2 μm, used for fabricating both ceramic components and BeO-UO2 nuclear fuel elements; (2) 2-8 μm, used primarily for fabricating beryllia bodies of 96-99.5% purity; and (3) ultrahigh density grains of specific size distribution for ad-mixing with resins and other organics to provide very high thermal conductivity coatings and/or potting compounds. Beryllia ceramics have these characteristics: extremely high thermal conductivity, particularly in the lower temperature range; excellent dielectric properties; outstanding resistance to wetting and corrosion by many metals and nonmetals; mechanical properties only slightly less than those of 96% alumina ceramics; valuable nuclear properties, including an exceptionally low thermal neutron absorption cross section; and ready availability in a wide variety of shapes and sizes. Like alumina and some other ceramics, beryllia is readily metallized by a variety of thick and thin film techniques. Although beryllia usually is selected for a desirable combination of properties, key to most applications is the material’s comparatively high thermal conductivity. Even at the highest temperatures, its thermal conductivity is four times that of dense alumina; and from room temperature to 500°C, seven to eight times greater. BeO’s thermal conductivity is quite dependent on purity. For example, increasing purity from 99% to 99.8% results in a 10-15% rise in conductivity. Physical Properties Specific gravity . . . . . . . . . . . . . . . . . . . . . . . . 3.008 Melting point, °C . . . . . . . . . . . . . . . . . . . . . . . . 2650 Softening temperature, °C . . . . . . . . . . . . . . . .>2000 Thermal conductivity, Btu/h/ft2/F/ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

BERYLLIUM OXIDE

CTE, 10-6/F, at... 212°F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 932°F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 1832°F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.9 Mechanical Properties Tensile strength, 103 psi, at... Room temperature . . . . . . . . . . . . . . . . . . . . . 18-20 1000°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Compressive strength, 103 psi, at... Room temperature . . . . . . . . . . . . . . . . . . . . . . . . 200 2000°F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Transverse strength, 103 psi . . . . . . . . . . . . . . . . . 35 Modulus of elasticity, 106 psi . . . . . . . . . . . . . . 40-45 Beryllia ceramic components are formed by hot pressing in graphite molds in induction furnaces, by slip casting, conventional dry pressing and extrusion. Major markets for BeO ceramics are: microwave tube parts such as cathode supports, envelopes, spacers, helix supports, collector isolators, heat sinks and windows; substrates, mounting pads, heat sinks and packages for solid-state electronic devices; and bores or plasma envelopes for gas lasers. Other uses: klystron and ceramic electron tube parts, radiation and antenna windows, and radar antennae. Beryllia’s exceptional resistance to wetting (and thus corrosion) by many molten metals and slags makes it suitable for crucibles for melting uranium, thorium and beryllium. Beryllia’s high general corrosion resistance has helped it capture new applications in the chemical and mechanical fields. And other uses in aircraft, rockets and missiles are predicted.

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BINDERS

BeO is tapped for nuclear reactor service because of its refractoriness, high thermal conductivity and ability to moderate (slow down) fast neutrons. The “thermal” neutrons that result are more efficient in causing fusion of U235. Nuclear industry uses for beryllia include reflectors and the matrix material for fuel elements. When mixed with suitable nuclear poisons, BeO may be a new candidate for shielding and control rod assembly applications. The market for electrically insulating, heat conductive encapsulants based on beryllia grain-polymer mixtures is both small and restricted. While these composites have thermal conductivities 10-20 times higher than those of other filled plastics, the handling restrictions necessitated by the presence of beryllia limit their use. BERYLLIUM OXIDE SUPPLIERS MATERION CERAMICS, INC. 6100 S. Tucson Blvd. Tucson, AZ 85706 (520) 746-0251 Fax: (520) 294-8906 Email: [email protected] Website: www.materion.com/ceramics BINDERS. Substances which serve to hold low green-strength ceramic materials and bodies together and give them sufficient bonding for handling and machining in all prefiring stages of manufacture. Their use reduces loss of ware and, in many cases, makes fabrication possible. Binders make possible the use of otherwise difficult clays; improve products made of heretofore unsatisfactory raw materials and

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BINDERS

bind powders that contain no natural plasticizers at all. According to Thumuer, a satisfactory binder should have a combination of attributes such that it would impart high strength, be nonabrasive, be free of noncombustible residual matter, burn out readily at low temperatures, not stick to die parts, not pick up atmospheric moisture and be readily dispersible as solution or emulsion. Another criterion is that it should not unduly add to final product cost. Materials being used for binders include clays, magnesium-aluminum silicate, natural gums, dextrine, pitch, asphalt, wax of several types, sodium silicate, alginates, glues, starches, lignin, microcrystalline cellulose, cellulose derivatives and thermoplastic resins. These are used in varying percentages, but most do not exceed 5% of batch weight. The sodium salt of pentachlorophenal, when added to water solutions of certain organic binders, prevents bacterial decomposition. (Material is acutely toxic so must be handled carefully and with full knowledge of its toxic properties.) Abopon. Viscous water-white liquid approximating the chemical composition of sodium borophosphate. When 100 cm3 of 1:1 solution is added on the basis of 100 lb of frit, the set of porcelain enamel is reduced and the bisque is hardened in a nature similar to that produced by gums. Tends to give a yellowish dirty color to titania-opacified cover coat enamels. Ammonium alum. Al2(SO4)3-(NH4)2 -SO4-24H2O. Soluble in water. Not in common usage because of its tendency to decompose during drying, thus imparting variable film strength. Tends to cause shorelining and scumming but has been used in porcelain enamel in amounts of 0.5% to increase set in sheet-iron ground coats and acid resisting cover coats. It has no effect on the acid resisting properties of the enamel. Dextrin. Cream-colored powder or granules formed by heating some form of starch with a little acid. Is used in ceramics chiefly as a binder. In matte glazes, practically the entire glaze is fritted and would settle to a cement-like mass if a flotative were not used. Dextrin also has proved of value in increasing the plasticity of clays, improving the working properties of porcelain bodies and promoting the adhesion of engobes and glazes to ware. Lignosulfonates (Lignin). Derivatives of the bisulfite pulping process, lignosulfonates are anionic, surface active polyelectrolytes. The lignin polymer with branched polyaromataic chains can be modified to vary by cation, degree of sulfonation and purity, and average molecular size. Lignin processing technology has developed aqueous-based dispersants and binders for various ceramic applications, including structural clays, whitewares, technical ceramics, refractories, and related areas of cement, concrete and gypsum board. As effective clay modifiers, lignin dispersants can improve tile and casting slip rheology, reduce free water for brick extrusion, and provide lubricity and plasticity for both extruded and dry-press ceramics. As a binder, lignin may increase both green and dry strengths of ceramic pieces with less than optimum body compositions. Lignin addition rates of 0.10-0.15% for fine grain and 0.20-2.0% for coarse ceramic materials will improve handling in prefiring stages of ceramic manufacturing. Tannic acid. Long used for increasing the plasticity of clays, it is not as effective as lignin extract in increasing the dry strength of clays or in deflocculant action. Magnesium-aluminum silicate. As supplied for ceramic binder purposes, it is the refined product of a naturally occurring smectite mineral. At least two such materials are commercially available. One has this analysis: 48.7% SiO2, 25.5% MgO, 0.6% Al2O3, 6.3% CaO, 1.8% Na2OK2O, 13.0% LOI. Best bonding properties with these binders are developed by dispersing the material into the preparation water. When added dry, it develops some bonding ability but is more effective as a lubricant.

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Materials Handbook

Magnesium-aluminum silicate binders consist of flat, plate-like flakes, which readily break down into submicron particles when agitated in water. Useful concentrations range from about 0.5-5.0%. Working and dry strength properties increase with increasing concentrations. These materials do not migrate on drying so that the properties imparted to the ceramic body are uniform from internal to external surfaces. As film formers, they add to surface hardness, but to a lesser degree than most other binders. Advantages in processing are ease in cleaning of equipment and no inherent tendency to cause corrosion of metal parts. It should be expected that magnesium-aluminum silicate will take part in ceramic body reactions and that it can influence fired properties. Paraffin. Ordinary paraffin, with a small percentage of carnauba wax for increased rigidity, is a good binder in some cases and can be molded cold with a consequent reduction in molding time. Material has been used in the manufacture of porcelain barriers in telephone transmitters. Requirements as to the strength of the molded part, sharpness of outline and dimensional tolerances chiefly determine the type of binder employed in each case. Starch. Henderson has reported the use of 0.3% ordinary laundry starch in a glaze very low in plastic content which settled and crawled badly. The starch acted as a floater and eliminated the crawling. On the negative side, starch sours on standing. Cellulose gum. (CMC.) Synthetic gum with excellent properties as a protective colloid for suspending, filmforming and binding. In whitewares it is used in both bodies and glazes, increasing plasticity and strength. It fires out readily and completely in the kiln. Methylcellulose. Synthetic gum proven effective as a temporary binder for refractories, structural clay products, whiteware and abrasives. In addition, it functions as a lubricant, wetting agent and plasticizer. As a film former, it toughens unfired glazes and improves bonding. It has been used to thicken and suspend glaze slips, and fired ware has been observed to possess a smoother finish. Trade named Methocel, the material has an extremely low ash content, does not melt, is nontoxic and does not deteriorate in storage. Manufactured under controlled conditions, its uniformity represents an important advantage. The material has a mild deflocculating effect varying with type (low, medium and high viscosity). Advantage can be taken of this effect to select the correct viscosity grade to give the necessary deflocculation. Microcrystalline cellulose. Ultrapure crystalline form of cellulose that’s clean burning (<50 ppm ash), nontoxic, very uniform and does not deteriorate in storage. Functions as a binder/lubricant (dry or wet mixing) in press powder compacts. When used as a binder/extrusion aid in extruded bodies, it controls shrinkage. Particle size range: 20-100 μm. Allows formation of porous or high-density fired bodies. Green and fired strengths enhanced significantly. Colloidal grades of microcrystalline cellulose, coproduced and dried with cellulose gum, function as nonmigrating binders and suspending agents in glaze slips. Performs as efficient binder/lubricants and extrusion aids in aqueous systems. Polyethylene emulsions. Utilized as combination binders and lubricants. Polyethylene glycols (PEGs). PEGs are widely used in ceramic processing. They are soluble in water and a variety of organic solvents, such as alcohols, ketones and chloroethylenes. Low molecular weight PEGs are viscous liquids and are used as internal or external lubricants and plasticizers. High molecular weight forms are waxy solids and are used as a binder in addition to being good lubricants and plasticizers. PEGs burn out over a temperature range of 175-350°C in air and 250-475°C in nitrogen. The ash content is low (<0.05%).

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PEG Compound 20M is a modified form of polyethylene glycol. It is made by chemically joining 2 mols of linear PEG8000 with the help of a linker. It has most of the properties of linear PEGs, but is amorphous in nature and is a stronger binder than an equivalent molecular weight linear PEG. Polyvinyl alcohol. Used for rendering certain glazes hard in the dry state so that they resist rub-off while being placed on kiln cars. The equivalent of 0.25% dry powder gives a very hard coating to glazes. It does not change on standing nor ferment, but cannot be used in borax frits due to salting out. Sodium silicate. Many grades are available with differences in their characteristics. Best results are obtained by consulting with the manufacturer. When used properly as a deflocculant, sodium silicate eases the drying of a body in that there is less strain in the ware due to the absence of much water. Ware dries hard and tough which decreases loss in the green state. Sodium metasilicate. Used as a mill addition in enamels for aluminum. Improves working properties and gives higher gloss values. Wax emulsions. Widely used as binders and lubricants because they permit easy dispersion of water-insoluble waxes throughout ceramic mixes. Wax emulsions act as lubricants in wet bodies and impart strength to the formed piece after drying. A major application is dustpressing of steatite and other nonplastic bodies. Dust pressing originated with the use of organic binders and is the only ceramic forming method that does not depend on the plasticity of the body to form the article. The chief advantage of this method is that dimensional tolerances are more easily maintained. Emulsions also are offered for use in extrusion mixes. Special emulsions are used in glazes to aid suspension, improve coverage and firing characteristics, and impart rub-off resistance (an area in which they’re particularly outstanding). Emulsions also have proved most effective as a green strength binder in floor and wall tile. A wax emulsion has been used as an adhesive for applying underglaze decals to semivitreous dinnerware. The emulsion replaces a starch size and varnish adhesive, and a moderate heat treatment prior to glazing is substituted for the harden-on fire formerly needed. Petroleum wax emulsions are easily removed from a ceramic body or glaze upon firing in an oxidizing atmosphere and leave no residue to adversely affect the properties of the ceramic article. BINDER SUPPLIERS LIGNOTECH USA INC. 100 Grand Ave. Rothschild, WI 54474 (715) 355-3603; (908) 612-0948 Fax: (715) 355-3648 Email: [email protected] Website: www.lignotech.com POLYMER INNOVATIONS, INC. 2426 Cades Way Vista, CA 92081 (760) 598-0500 Fax: (760) 727-3127 Email: [email protected] Website: www.polymerinnovations.com WESBOND CORP. 1135 E. 7th St. Wilmington, DE 19801 (302) 655-7917 Fax: (302) 656-7885 Website: www.wesbond.com

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BINDERS

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BORAX

BINDER SUPPLIERS CONTINUED

ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com BISMUTH OXIDE. Bi2O3. Mol. wt. 466.0; sp. gr. 8.2-8.9; m.p. 820-860°C. Insoluble in water but soluble in acids. Derived from ignition of bismuth nitrate. Bismuth is a satisfactory constituent of optical glasses. Amounts up to 50% have been used experimentally in glasses of the general molecular formulas: 100SiO2-40Na2O11Bi2O3 and 100SiO2-40K2O-xBi2O3. Compared with corresponding glasses containing lead oxide (PbO) instead of bismuth, these glasses exhibited greater durability, higher specific gravities and higher refractive indices. Any tendency on the part of bismuth to impart a gray color to the glass may be counteracted by the addition of small amounts of arsenic along with an oxidizing agent. Calcined bismuth oxide is used as an ingredient in fluxes for fired-on types of conductive silver paints. It also can be used by itself as a flux for bonding metallic silver flake to ceramic bodies. Bismuth oxide is now used to replace lead oxide in the whitewares industry for consumer products such as bone china, fine china and earthenware. The color palette of the glaze decorations must be adjusted for the bismuth containing glaze. Bismuth glazes approach the properties of lead-bearing glazes but at higher cost. BISMUTH TELLURIDE. Bi2Te3. Mol. wt. 800.98; m.p. 585°C; rhombohedral structure, lattice constant 10.45 x 10-3, 248x; band separation (300 K) 0.16 eV; mobility (300 K), cm2/Vs, >580 electrons, >400 holes. Bi2Te3 is usually prepared by reacting nearly stoichiometric amounts of the elements and allowing directional freezing to take place. Bi 2 Te 3 is currently the best known thermoelectric material, but is used only in cooling devices because it loses its semiconducting properties above approximately 100°C. Bismuth telluride exhibits a resistivity of 103 ohm-cm and a thermal conductivity about 0.005 that of copper. This combination gives the material a high thermoelectric power of about 200 mV/C. A refrigerator using thermo-elements of bismuth telluride studied at Battelle Memorial Institute exhibited a maximum temperature difference between hot and cold junctions of 49°C when operated under no-load conditions. Refined means for preparing the material have made possible temperature differences of 68°C. BISMUTH TITANATE. Bi2O3-2TiO2. Typical compositions contain 73.5 wt% Bi2O3 and 26.3 wt% TiO2. In class I ceramic capacitors, bismuth titanate is vital to obtaining the proper temperature coefficient. Also used as a sintering aid in class II capacitor compositions. BONE ASH. (Bone, calcium phosphate.) Product of calcined bones containing 67-85% calcium phosphate, 3-10% calcium carbonate, 2-3% magnesium phosphate and small amounts of caustic lime and calcium fluoride. Approximate formula: 4Ca3(PO4)2CaCO3 (mol. wt. 1340). The names bone ash and calcium phosphate are used interchangeably, although the former is a crude product and the latter a pure compound. Properties of Ca3(PO4)2 include: mol. wt. 310; sp. gr. 2.3; RO equivalent weight

103. Prepared by precipitation from mixtures of sodium phosphate and calcium chloride solutions. In enamels, bone ash or the precipitated phosphate is used to a slight extent as an accessory opacifier. When a sufficient amount of either is used to make the enamel opaque, it causes a dull luster by producing minute pinholes. If not carefully worked, chipping and blistering of the enamel will occur. The maximum amount which may be used in cast iron enamels is 1-2%. Bone ash is used occasionally in glazes at low temperatures to produce opacity, but if used in too large an amount or at too high a temperature, blistering will occur. In pottery, bone ash is used extensively in England in the manufacture of world-famous bone china, which is characterized by superior translucency and whiteness. When prepared for the body, the bone must be calcined thoroughly and ground through an exceptionally fine screen. If the bones ash slurry is to be dried for shipment to be used at some future date, it must be placed in plastic bags, or other air-tight containers, to prevent reaction with CO2 in the air which can dramatically change the properties of plastic body or casting slips. The manufacture of bone china is difficult because bone ash, being nonplastic, destroys much of the workability of the body. In addition, bone china usually contains china clay and Cornish stone, which result in a very high firing shrinkage and make the ware sensitive to overfiring. Another hazard is the pronounced tendency to go offcolor in bisque, glost and decorating processes. Small amounts of bone ash in a chinaware body increase the fluxing action of the feldspar, due to its 15% calcium carbonate content. The material has a strong tendency to form minerals of the apatite group, and this probably happens inside the body. Bone china, therefore, probably consists of a glassy phase, relatively high in calcium oxide, which accounts for the relatively high refractive index and resultant high translucency. In addition to minor amounts of quartz and mullite, the chief crystalline constituent probably is apatite, possibly a mixture of fluorapatite and hydroxyapatite. Calcium phosphate also can act as an opacifier in the production of opal glass. From 8-30 lb/1000 lb sand are usually used. The P2O5 compound, obtainable from bone ash, has a curious effect on the higher oxide of iron. It forms colorless compounds, which explains why it has been possible to make some colorless, heat-absorbing glasses that absorb the near-infrared portion of the spectrum. This suggests the possibility of using bone ash in commercial colorless glasses to cancel the effect of higher iron oxide content in other batch ingredients than is ordinarily tolerated today. Sodium phosphate. Na2-HPO4-H2O. Is occasionally used in place of bone ash because it has a more constant composition. With glasses of the type K2O-RO-3SiO2 or K2O-RO0.5B2O-3SiO2, variation in the kind of alkalies has no effect on the coloration produced by bone ash. Boric acid intensifies the action of bone ash on lead, barium and zinc glasses, in decreasing order of influence. RO content has a major influence on borosilicate glasses. The phosphate Na2HPO4H2O acts similarly to bone ash. With calcium phosphate (Ca3(PO4)2) in glasses of the first type, lead favors opalescence most, followed by barium. In glasses of the second type, lead and barium aid the action of the phosphate, zinc being less active. The coloring power of Na2HPO4 is weaker than that of the other two agents in glasses of the second type, but no remarkable difference is observed in the first type. Opalescence appears due to the suspension of P2O3. BORAX. (Sodium tetraborate.) Na2O-2B2O3-10H2O. Mol. wt. 381.4; sp. gr. 1.73 (25°C); hardness 2.0-2.5 Mohs; begins to melt in its own water of crystallization at 60.8°C. Soluble in water, acids, glycol, glycerol and other solvents. Practically all American borax comes from California. The mineral tincal is mined in the Mojave Desert and is processed and mar-

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keted as borax. Borax also is prepared by evaporation and purification of brines from Searles Lake. Theoretical composition of borax: 16.25% sodium oxide, 36.51% boric acid, 47.24% water of crystallization. The water of crystallization is eliminated during fusion with other ceramic raw materials, leaving 52.76 wt% sodium and boric oxides to form part of the ceramic composition. Purity of ordinary commercial borax is guaranteed 99.5% min; original impurities being largely clay or other soluble salts. Borax is obtainable in large crystal, powder and granular form, the last being regarded as the most practical and economical for ceramic use. The 10 molecules (47.24%) of water of crystallization in borax are subject to a small normal variation, the mineral losing water slowly during storage. In cases where considerable accuracy of batch composition is desired, it is necessary to determine and make proper adjustment for the actual water content immediately prior to use. This determination is accomplished by fusion or titration, the latter method being preferred. Sodium tetraborate pentahydrate. Na2O-2B2O3-5H2O. Mol. wt. 286.6; sp. gr. 1.815 (25°C). Typical composition: 21.621.8% sodium oxide, 48.6-48.8% boric oxide. An economical replacement for borax. Theoretically 76.4 lb are equivalent to 100 lb of regular borax. The commercial product has about 4.75 rather than 5 mol of water of crystallization. Anhydrous borax. (Fused borax.) Na2O-2B2O3. Mol. wt. 201.27; sp. gr. 2.36; m.p. 742°C; soluble in water. Its rate of solubility is considerably slower than that of borax at 20°C but about the same at 60°C. Theoretical composition: 30.8% sodium oxide, 69.2% boric oxide. Theoretically, anhydrous borax contains no water of crystallization, and actual analyses show less than 0.5% water. It may be substituted for ordinary borax, approximately 53 lb being equivalent to 100 lb of hydrated material. Unlike borax, it does not puff or swell to a light fluffy mass during melting, and, therefore, its use minimizes segregation and loss, particularly in furnaces operated under strong drafts. In cases where relatively large amounts of boric oxide are required in the finished product, the substitution of anhydrous borax for ordinary borax can substantially increase production. Due to its concentrated form, larger yields are possible and less time is required for melting, the water content having previously been eliminated and there being no insulating action due to the absence of the light, porous stage which is evident in the melting of ordinary borax. Anhydrous borax saves fuel, involves the handling and storage of less material and, in general, makes for a smoother and more complete process. Borates in glazes. Borax is widely used as a flux for glazes on earthenware, artware and other types of ceramic bodies. Boric oxides share with silica the property of combining with bases to form glassy compounds after fusion. The readiness with which boric oxide combines with bases finds application in the production of pottery colors from metallic oxides; the shades obtained often vary according to the amount of boric oxide used. It also has an important function in reducing viscosity of glazes; by the addition of a little borax, the most viscous glaze can be made to heal better. Borax also tends to produce higher gloss in a glaze and lowers the maturing temperature. In raw porcelain glazes, borax may advantageously be added in small amounts. An excess, however, induces defects such as crazing, blistering, injury to underglaze colors, injury to the stability of the glaze and thickening of the glaze to an unworkable jelly-like state. Borax is largely used in glazes where it is required to keep the amount of lead as low as possible and yet produce a glaze of moderately low melting point. By decreasing the boric acid content, where it is included in the glaze formula, and substituting an equivalent amount of silica, a glaze is made harder, more brilliant and more durable. The introduction of boric acid into the glaze as a substitute for silica, however, decreases the coefficient of expansion. Thus, the relative amounts of boric acid CERAMIC INDUSTRY ³ January 2012

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BORAX

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BORON CARBIDE

and silica may be proportioned to achieve the best possible fit between body and glaze. Borates in enamels. Borax is one of the principal ingredients of porcelain enamels. The amount of borax in the frit batch for sheet-steel ground-coat enamels varies from 20-45%, for sheet-steel cover coats from 15-40%, and for dry-process ground coats from 20-45%. About one-third of the amounts indicated represent boric oxide itself. In enamels, borax is one of the most active of all the fluxes used. It has a comparatively low melting point and vigorously attacks other ingredients, thus accelerating the rate at which the enamel is brought to a uniform molten state. Borax also imparts important thermal properties necessary to assure proper fit of the enamel to the base metal. Borax imparts high luster, strength, toughness and durability, and assists in obtaining deep brilliant colorings, though it shortens the firing range of most enamels. Increasing the boric oxide content of a mill liquor decreases the scumming of an enamel caused by firing at too low temperatures. Better mobility and yield values of an enamel are attained by the use in the slip of hard water with 0.4-0.7% borax. Pitting caused by crystallization of borax on the surface of an enamel during drying will burn out in firing. Borax helps to prevent crazing, but excessively large amounts will cause tearing and crawling and will reduce the efficiency of mill-added opacifiers. Borates in glass. Borax is indispensable to the manufacture of heat-resisting glass, fiber glass and other special glasses in which the presence of boric oxide, in relatively large percentages, is essential to obtain thermal durability, corrosion resistance and other important properties. In general, those glasses containing the greatest amount of boric oxide show a minimum expansion, a property which is of great importance in obtaining thermal durability. For this purpose, the thermal properties of the glass are not of primary importance and smaller quantities are employed to gain other desirable results. With the average batch, the boric oxide content of the resultant glass will run about 0.6-1.5%. In these amounts borax has been found to facilitate melting and refining to a considerable degree; increases in production capacity of 20-50% have been reported. In the event increased melting capacity cannot be employed, it is usually possible to decrease the melting temperature required to produce normal requirements with consequent savings in fuel and wear and tear on melting equipment. Since borax generally decreases the viscosity of glass, its use should be accompanied by lower temperatures in the working end of the furnace. Borax also tends to shorten the working range and is, therefore, advantageous in connection with the use of high-speed machines. In addition to its beneficial effects in melting, the presence of small amounts of borax in ordinary sodalime-silica glass (resulting from use of borax in the batch) imparts greater brilliance, strength, durability and thermal shock resistance. It also decreases the tendency for glass to devitrify or crystallize. With large melting units, the rate of production of good seed-free glass does not necessarily increase in direct proportion to the borax content of the batch, but probably reaches a maximum efficiency in glasses containing about 1.0-1.5% B 2 O 3 . Use of borax in such batches usually narrows the setting range, thus permitting greater speeds for the automatic fabrication of ware on bottle machines. Boric oxide in the glass composition has been found to increase both the impact and tensile strength of glass containers. It also decreases the coefficient of expansion and increases rate of heat transfer and strength, all of which play important roles in thermal endurance. The use of 1% B2O3 often results in a better distribution and less checking in machine-made ware, besides the other advantageous properties mentioned above.

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Materials Handbook

The presence of boric oxide in glass considerably improves its appearance, making the glass more brilliant and of better color, while the surface appears smoother and freer from minute imperfections. Boric oxide itself has no effect on color, but as the rate of melting is increased, less decolorizer is needed. This is true only for those batches in which moderate amounts of boric oxide are used. In heat-resisting glasses, high in boric acid, only neodymium functions satisfactorily as a decolorizer. (See RARE EARTHS.) The effect of replacing soda and silica with boric oxide in a Fourcault glass sheet has been investigated. The glass composition: 72.5% SiO 2, 1.05% Al 2O 3, 10.69% CaO, 15.67% Na2O. The substitution of boric oxide for silica increased both the melting and refining rates, while the substitution of boric oxide for soda decreased the melting rate only when amounts exceeded 5%. From the foregoing it seems evident that moderate amounts of borax (60-120 lb/ton sand batch) will facilitate melting, allow increased fabricating speeds and improve the quality of the resultant glassware. The extent to which melting is facilitated and quality is improved depends largely on the general composition of the batch employed and the specific operating conditions in each individual glass plant. However, it may be assumed that the amount of borax used in the batch bears a close relationship to the results obtained. When particularly large increases in melting rate are desired (durability, thermal properties, etc. of secondary importance) the borax may be used directly to replace sand. When durability and thermal properties are most important, the borax is substituted for soda. BORAX SUPPLIERS RIO TINTO MINERALS 8051 E. Maplewood Ave. Greenwood Village, CO 80111 (303) 713-5000 Fax: (303) 713-5769 Website: www.riotintominerals.com BORIC ACID. (Boracic acid.) 0.5(B2O3-3H2O). Mol. wt. 61.83; sp. gr. 1.517 (14°C); m.p. 171°C (in closed space); soluble in hot water. Marketed as a technically pure preparation, containing 56.5% B2O3. Boric acid is produced by treatment of sodium or calcium borates with sulfuric acid and also by liquid-liquid extraction from complex salt brines. Also found in Italy in limited quantities as the mineral sassolite. Boric acid is used to introduce boric oxide into ceramic compositions. It is not as economical a source of boric oxide as is borax, but is the material of choice if sodium oxide must be eliminated or minimized in the finished product. BORIC ACID SUPPLIERS RIO TINTO MINERALS 8051 E. Maplewood Ave. Greenwood Village, CO 80111 (303) 713-5000 Fax: (303) 713-5769 Website: www.riotintominerals.com SQM NORTH AMERICA CORP., INDUSTRIAL 2727 Paces Ferry Rd. S.E. Ste. 2-1425 Atlanta, GA 30339-6160 (770) 916-9426 Fax: (770) 916-9401 Email: [email protected] Website: www.sqm.com BORIDES. Borides describe any of a number of compounds containing boron. (See specific categories for additional details.)

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BORIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com BORON. B. At. wt. 10.811; m.p. 2075-2175°C; b.p. 2500°C. Dark gray rhombohedral crystals with metallic luster, density 2.34-2.55 g/cm3; or brown to dark brown amorphous powder, density 2.37-2.40 g/cm3. Insoluble in water. Partially oxidized surfaces result in hydrophilic character. Boron has a high thermal neutron capture cross-section (750 barn) due to the B10 isotope (18.3 wt% in naturally occurring boron). Boron and some of its compounds, notably boron carbide, are therefore widely used for neutron absorption in nuclear reactors. The element has an extremely high calorific value (308 kcal/ mole, compared to 94 kcal/mole for carbon), allowing its use in solid/slurry fuel formulations. Fine amorphous boron powders oxidize slowly in air at room temperature, and can be sensitive to heat, impact and humidity, especially in the presence of oxidizers. Fine powders ignite in air at about 800°C. Reaction with nitrogen proceeds above 1200°C and with carbon above 1300°C. Boron is a p-type semiconductor dopant. Available in various purity grades, elemental boron is used in research, industrial and aerospace applications such as solid fuels and slurries, ceramic formulations, nuclear absorption, explosive primers and as an alloying additive. Metal borides may be synthesized from the element. BORON SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com BORON CARBIDE. B4C. Mol. wt. 55.26; m.p. 2450°C; b.p. 3500°C; density 2.52 g/cm3. Black or dark gray, sooty when fine powder, glassy when dense. Theoretical boron content 78.3 wt%. Boron carbide is the third hardest material known— after diamond and cubic boron nitride (CBN)—and the hardest among mass-produced materials. Above 1300°C, boron carbide is even harder than diamond and CBN. This light ceramic material is very strong, with a 4-point flexSupplier listings indicate paid advertising.

2012 Edition

BORON CARBIDE BORON CARBIDE SUPPLIERS CONTINUED

ural strength of 50,000-70,000 psi and a compressive strength of 414,000 psi (strength depends strongly on densification method and microstructure). The high strengthweight ratio makes B4C especially attractive for armor and aerospace applications. Low thermal conductivity (29-67 W/mK) combined with a large Seebeck coefficient (200-300 mmV/K) makes B4C an efficient p-type thermoelectric, especially at elevated temperatures. Electrical resistivity ranges from 0.1-10 ohm-cm, and is sensitive to hydrostatic pressure. Different commercial grades of B4C are available, based on boron content and particle size. Technical (65-78% B), nuclear (76.5% B min) and high-purity (77-80% B) grades can be obtained with sizes ranging from coarse grits up to 50 mm (5-20 mesh) to submicron powder. The B4C ratio is typically in the range of 3.9-4.2. Boron carbide parts are fabricated by hot pressing, sintering and sinter-HIPing. Industrially, densification is carried out by hot pressing (2100-2200°C, 20-40 MPa) in argon. The best properties are obtained when pure fine powder is densified without additives. Pressureless sintering to high density is possible using ultrafine powder with additives (notably carbon). Less expensive than hot pressing, sintering also can be used for more complex shapes. Special part formulations include bonding B4C with fused sodium silicate, borate frits, glasses, plastics or rubbers to lend strength, hardness or abrasion resistance. Boron carbide-based cermets and metal matrix composites (especially Al/B4C, Mg/ B4C, Ti/B4C), and ceramic matrix composites (e.g. TiB2/B4C) have unique properties that make these materials suitable for highly specialized applications. Superior ballistic performance, hightemperature strength, light weight, corrosion resistance and hardness make these composites especially attractive. Boron carbide shapes can be reaction bonded using silicon carbide as the bonding phase. B4C-carbon mixtures are formed, then reacted with silicon to create the silicon carbide bond. SiC also can be used as a sintering aid for boron carbide and vice versa. As an abrasive, B4C is used for fine lapping, polishing, wire sawingand ultrasonic grinding and drilling, either as a loose powder or as a slurry. Tendency to oxidize at workpiece temperatures precludes its use in bonded abrasive wheels. Abrasion-resistant parts made from boron carbide include spray and blasting nozzles, bearing liners and furnace parts. Boron carbide’s refractory properties, in addition to its abrasion resistance, are of value in the latter application. Boron carbide is chemically inert, although it reacts with oxygen at elevated temperatures and with white hot or molten metals of the iron group, and certain transition metals. B4C reacts with halogens to form boron halides—precursors for the manufacture of most nonoxide boron chemicals. B4C also is used in some reaction schemes to produce transition metal borides. Boronizing packings containing B4C are used to form hard boride surface layers on metal parts. As an additive to carbon-bonded refractories, B4C decreases the oxidation of the carbon and increases lifetime of the refractory. Boron carbide and elemental boron are used for nuclear reactor control elements, radiation shields and moderators.

BORON CARBIDE SUPPLIERS CONTINUED

® Advanced Material Specialists, Inc.

CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com

ESK CERAMICS GMBH & CO. KG Max-Schaidhauf-Str. 25 Kempten 87437 Germany (49) 831-56180 Fax: (49) 831-5618345 Email: [email protected] Website: www.esk.com

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HAI ADVANCED MATERIAL SPECIALISTS INC. 1688 Sierra Madre Cir. Placentia, CA 92870 (877) 411-8971 Fax: (877) 411-8778 Email: [email protected] Website: www.haiams.com

SAINT-GOBAIN CERAMICS, STRUCTURAL CERAMICS, HEXOLOY® PRODUCTS 23 Acheson Dr. Niagara Falls, NY 14303-1597 (716) 278-6233 Fax: (716) 278-2373 Email: [email protected] Website: www.hexoloy.com H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

BORON CARBIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

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CERAMIC INDUSTRY ³ January 2012

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BORON CARBIDE

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CALCIUM PHOSPHATE

Materials Handbook

BORON CARBIDE SUPPLIERS CONTINUED H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com SUPERIOR GRAPHITE CO., INDUSTRIAL PRODUCTS 10 S. Riverside Plaza Chicago, IL 60606 (312) 559-2999; (630) 841-0099 Fax: (312) 559-9064 Email: [email protected] Website: www.superiorgraphite.com

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com BORON NITRIDE. BN. A highly refractory material with physical and chemical properties similar to carbon. Graphite-like (g-BN), wurzite (w-BN) and zinc blende (z-BN) are known polymorphs of BN corresponding to the graphite (hexagonal) and diamond (cubic) structures. Transformation of g-BN to w-BN occurs at pressures above 12 GPa at relatively low temperature (230°C). Transformation of w-BN to z-BN occurs above 1300°C and pressures above 5.5 GPa. Zinc blende (z-BN) is stable above 5.5 GPa and from 1100 to 1500°C. All forms of BN are good electrical insulators, possessing band gaps of several eV; electrical resistance of the hexagonal form varies from 1.7 x 1013 ohm-cm at 25°C to 3 x 104 ohm-cm at 1000°C and is little affected by frequency. The dielectric constant of hexagonal BN is 3 with the electric vector parallel to the basal plane and 5 perpendicular to the plane. Consistent with the short interatomic distances and light atomic weights, all forms of BN are very good thermal conductors. Boron nitride is chemically inert in most environments, resisting attack by mineral acids or wetting by glasses, slags and molten oxides; cryolite and fused salts; and most molten metals including aluminum. Its rate of oxidation in air is negligible below 1100°C. Hexagonal boron nitride is commonly synthesized as a fine powder. Powders will vary in crystal size, agglomerate size, purity (including % residual B2O3) and density. BN powders can be used as mold release agents, high temperature lubricants, and additives in oils, rubbers and epoxies to improve thermal conductance of dielectric compounds. Powders also are used in metal- and ceramicmatrix composites to improve thermal shock and modify wetting characteristics.

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Hexagonal boron nitride may be hot pressed into soft (Mohs 2) and easily machinable, white or ivory billets having densities 90-95% of theoretical (2.25 g/cm3). Thermal conductivities of 17-58 W/mK and CTEs of 0.4-5 x 10-6/C are obtained, depending on density, orientation with respect to pressing direction and amount of boric oxide binder phase. Because of its porosity and relatively low elastic modulus (50-75 GPa), hot pressed boron nitride has outstanding thermal shock resistance and fair toughness. Pyrolytic boron nitride, produced by chemical vapor deposition on heated substrates, also is hexagonal; the process is used to produce coatings and shapes having thin cross sections. Uses for hexagonal boron nitride shapes include crucibles, parts for chemical and vacuum equipment, metal casting fixtures, boron sources for semiconductor processing and transistor mounts. Cubic boron nitride is second in hardness only to diamond. It is used for high-performance tool bits and in special grinding applications. Cubic BN tooling typically outlasts alumina and carbide tooling and is preferred in applications where diamond is not appropriate, such as grinding of ferrous metals. BORON NITRIDE SUPPLIERS

ESK CERAMICS GMBH & CO. KG Max-Schaidhauf-Str. 25 Kempten 87437 Germany (49) 831-56180 Fax: (49) 831-5618345 Email: [email protected] Website: www.esk.com H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com

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C

ADMIUM FLUORIDE. CdF2. Mol. wt. 150.41; m.p. 1000°C; density 6.64 g/cm3. Cubic, white crystals are soluble in water and HF and other acids.

CADMIUM OXIDE. CdO. Mol. wt. 128.41; m.p. >1426°C; density 6.95 g/cm3. Brown amorphous material insoluble in water and alkalis, but soluble in acids and ammonia salts. CALCINED FIRE CLAY. (See GROG.) CALCINED FIRE CLAY SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com CALCIUM ALUMINATE. CaAl2O4. Mol. wt. 158.02; m.p. 600°C; density, 3.67. Colorless rhombohedral or monoclinic crystals dissociate in cold water, are soluble in HCl and insoluble in H2SO4 and HNO3. The mineral Ca3Al2O6 has a cubic structure and dissociates at 1535°C. Used in synthetic slag applications—primarily in ladle metallurgy operations. CALCIUM BORIDE. CaB 6. Mol. wt. 105; m.p. 2160ºC (4055ºF); sp. gr. 2.45; hardness 2740 Vickers. CALCIUM CARBONATE. Precipitated calcium carbonate, in low-micrometer sizes, is used as an inorganic filler in basing cements. These cements consist of a two-stage phenolformaldehyde resin, calcium carbonate filler and enough hexamethylenetetramine to catalyze the reaction of the resin with heat. Various organic dyes are sometimes added. Material also can be used for insulating coatings for ceramic capacitors and printed circuits. (See LIME.) CALCIUM CARBONATE SUPPLIERS SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com CALCIUM METABORATE. Ca(BO2)2. Mol. wt. 125.72; m.p. 1100°C (2192°F). (See BORON.) CALCIUM MOLYBDATE. CaMoO4. Melting point unknown but believed to be quite high. A white compound very sparingly soluble in water. Gives fair adherence and fair opacity in clear enamels when used in amounts >6%. Because of its refractory nature, it is difficult to decompose in enamels. Under severe heat treatment, 1-2% calcium molybdate gives excellent adherence in antimony-bearing enamels or clear ground coats in conjunction with Sb2O3. Being almost insoluble, it makes a good mill addition for draining enamels. CALCIUM NITRATE. Ca(NO3)2-4H2O. Mol. wt. 236.16. White crystals readily soluble in water. Will absorb moisture from air. Used as an oxidizing agent in zircon and titania opacified enamels. Use is limited to sprayed-on enamels because of tendency to cause blistering along edges of dipped ware. CALCIUM OXIDE. (See LIME.) CALCIUM PHOSPHATE. (See BONE ASH and TRICALCIUM PHOSPHATE.) Supplier listings indicate paid advertising.

2012 Edition

CALCIUM PHOSPHATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com CALCIUM SILICATE. CaSiO3. (See WOLLASTONITE.) CALCIUM SULFATE. (See PLASTER OF PARIS.) CALCIUM SULFATE SUPPLIERS ALLIED CUSTOM GYPSUM 1550 Double Dr. Norman, OK 73069 (405) 366-9500 Fax: (405) 366-9515 Email: [email protected] Website: www.alliedcustomgypsum.com CALCIUM TITANATE. CaTiO3. High-dielectric material which, when fired to maturity at 2450-2500°F as a single-component body and tested at 1 kHz and 1 MHz, exhibits a dielectric constant of 150-175, a power factor <0.07% and a negative temperature coefficient of capacity of 1400 ppm/°C. The power factor of calcium titanate is fairly constant from -125-50°C, but increases sharply from 50-120°C. Its dielectric constant decreases rapidly over the temperature range -125-120°C. The dielectric constant is stable over the 102-107 Hz frequency range. Calcium titanate compositions can be either dry pressed or slip cast and are usually fired to vitrification at a peak temperature of 2300-2400°F. Other steps in the manufacturing operation are similar to those used for barium titanate. Calcium titanate is relatively dense (3.17 g/cm3, powder; 4.02 g/cm3, fired) and exhibits linear thermal expansion from -70°C to more than 150°C. To form high K bodies, calcium titanate is used as a single component or is blended with barium titanate and other alkali earth zirconates and/or titanates. In piezoelectric applications, it is added to barium titanate and barium titanate-lead titanate bodies. Normally, 3-5% calcium titanate is used. CALCIUM ZIRCONATE. CaZrO3. Refractory prepared from equimolar proportions of CaCO3 and ZrO2, which are dry pressed and fired to a final temperature of 1850°C. Exhibits low firing shrinkage. Stable to 1750°C under highly reducing conditions. Nonreactive with BeO, Al2O3, MgO or ZrO2 at 1500°C, but is highly reactive with SiO2-bearing refractories at this temperature and below. Also used as an additive (3-10%) to titanate dielectrics to obtain bodies with special electrical properties. CARBON AND GRAPHITE. Carbon boasts high resistance to thermal shock, and a strength that increases with temperature. It is chemically inactive, not wet by most molten metals and resists abrasion and erosion. Graphite, in addition, has high thermal conductivity, low thermal expansion, high electrical conductivity, is relatively pure and is easily machinable. This unique combination of physical and chemical properties has resulted in numerous applications. Among them: lighting carbons; carbon-graphite and metal-graphite brushes for motors and generators; welding carbon products; electrodes for electrometallurgical and electrochemical industry use; carbon, graphite and impervious carbon and graphite pipe, fittings, valves, pumps, towers, heat exchangers, Raschig rings, tubes, brick, tile and special structural shapes for handling and processing corrosive materials; and porous

CALCIUM PHOSPHATE

carbon and graphite products for filtration and gas dispersion. Activated carbon is used for solvent recovery and absorption of odors and vapors. In addition, carbon and graphite products have many important metallurgical applications. These include carbon linings for hearth and wall sections of blast furnaces and ferroalloy furnaces; phosphorus furnaces; aluminum pot linings; cinder notch liners; liners for run-out troughs and pickling tanks; carbon and graphite ingot mold plugs and tool inserts; and graphite fluxing tubes for purification of metals; thermocouple sheaths; riser rods for steel castings; molds for ingots, billets, centrifugally cast bushings, static cast rods and other simple castings; core rods; sintering boats and trays; crucibles for induction and resistance melting; and skimmer floats. Special applications of carbon and graphite include switch and circuit breaker contacts; rheostat disks; steam turbine packing; piston rings; stuffing box packing; thrust rings for automobile clutches; back plates, diaphragms and granular carbon for telephones; anodes and grids for electronic devices; and, in the form of pure graphite powder, a lubricant and constituent of lubricating grease. Graphite also is used as rudder vanes for guided missiles, nozzles for rocket motors and tooling for the manufacture of thermosetting and thermoplastic composite parts. Carbon and graphite electrodes have made possible the electric arc furnace. Graphite anodes have been an important factor in the development of electrolytic processes. Nuclear grades of graphite are used as moderators, thermal columns, reflectors, and shields in nuclear reactors. Specialty grades of graphite are used in many highly technical applications, including semiconductor processing, mechanical heart valves, electrical discharge machining and electrochemical cells.

³

CHALK

CEMENT, HIGH-TEMPERATURE. See CEMENT, REFRACTORY. CEMENT, HIGH-TEMPERATURE SUPPLIERS MORGAN THERMAL CERAMICS P.O. Box 923 Augusta, GA 30903 (706) 796-4200 Fax: (706) 796-4328 Email: [email protected] Website: www.morganthermalceramics.com CEMENT, REFRACTORY. Refractory cement is a premixed, high-temperature silicate mortar for setting, coating, or repairing firebrick. It is commonly used as the mortar between firebricks when building fireplace fireboxes. Source: www.rutland.com/productinfo/refractory-cement.html

CEMENT, REFRACTORY SUPPLIERS

MORGAN THERMAL CERAMICS P.O. Box 923 Augusta, GA 30903 (706) 796-4200 Fax: (706) 796-4328 Email: [email protected] Website: www.morganthermalceramics.com CERIUM FLUORIDE. Cerium fluoride (CeF3) is made up of white crystals and has a melting point of 1460°C. Source: www.metall.com.cn/cef.htm

CERIUM FLUORIDE SUPPLIERS CARBON BLACK. Any of various colloidal black substances consisting essentially of elemental carbon prepared by partial combustion or thermal decomposition of hydrocarbons. CARBON BLACK SUPPLIERS

CANCARB LTD. 1702 Brier Park Cres. N.W. Medicine Hat, AB T1C 1T8 Canada (403) 527-1121 Fax: (403) 529-6093 Email: [email protected] Website: www.cancarb.com CATALYSTS. A substance which by its presence, will change the rate of a chemical reaction but which itself will be unchanged in composition or quantity after the reaction is completed. CEMENT. Cement is the basic ingredient of concrete, and is composed of calcium, silicon, aluminum, iron, limestone, and other ingredients. CEMENT SUPPLIERS MORGAN THERMAL CERAMICS P.O. Box 923 Augusta, GA 30903 (706) 796-4200 Fax: (706) 796-4328 Email: [email protected] Website: www.morganthermalceramics.com

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PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com CERIUM OXIDE. CeO2. Mol. wt. 172; m.p. 2800°C; softens at 100-1200°C. Insoluble in water, soluble in mineral acids. Marketed in the oxide form or as other salts, nitrates and carbonates. Available purities: 95-99.9%. Also available in concentrate form (60% CeO2 min). Applications in glass include use in medical tubing for UV protection and in color TV face plates for antibrowning. Used in optical filters to reduce UV haze and for UV protection in pink ophthalmic glass. Cerium oxide is used in gamma radiation shielding glasses and also is a major constituent in glass polishing compounds. In combination with titanium oxide, cerium oxide produces a yellow glass. In the automotive catalytic converter, cerium oxide is used to stabilize alumina in the alpha phase. It also is used as an opacifier for special effects in the tile industry, and as a replacement for tin oxide in the porcelain enamel field. Cerium oxide is being considered as a sintering aid for silicon nitride. (See RARE EARTHS.) CERMETS. Cermets (ceramic metals) are composites formed from a ceramic material and a metal. They enjoy wide use in cutting tools and other applications that require high hardness and high temperature and wear resistance, such as coatings and armor. CESIUM. (See RUBIDIUM.) CHALK. (See LIME.) CERAMIC INDUSTRY ³ January 2012

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CHROME ALUMINA

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CHROMIUM OXIDE

CHROME ALUMINA. (See ALUMINA, CHROME.) CHROME ALUMINA SUPPLIERS

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com CHROMITE. The predominant constituent of chrome ore. Associated with it in these ores are minor amounts of silicate gangue minerals such as serpentine, chlorites, pyroxenes and feldspars. Chromite is a spinel group mineral of composition (Mg,Fe)O(Cr,Al,Fe0)2O3. This also can be expressed as R+2OR+32O3, with RO:R2O3 ideally equal to 1. The mineral is jet black to grayish or brownish black with a luster ranging from brilliant shiny to pitchy, resinous, dull and submetallic. The main uses of chromite are for chromium metal (ferralloys and chromium electroplating), chromium chemicals, and for chromite-bearing refractories. Other uses: foundry sand, colorant in production of green bottles, pigment in manufacture of gray face brick, ingredient for foundry washes and major constituent of some refractory mortars. (See CHROMIUM OXIDE.) CHROMITE SUPPLIERS

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com CHROMIUM BORIDES. CrB, Cr2B, CrB2, Cr3B2, Cr3B4. Formed by fusion of chromium and boron in an electric arc (produces CrB) or by reaction of Cr2O3 and boron in an electric furnace. Five phases are found in the Cr-B system. CrB, Cr2B, Cr3B2 and Cr3B4 are orthorhombic; CrB2 is hexagonal. All borides are stable in HF, HCl, HNO3, H2SO4 and alkali solutions, but are subject to oxidation, the rate being very temperaturedependent. CrB 2’s properties include: density 5.6 g/cm 3; m.p. 2760°C; tensile strength 106,000 psi; thermal conductivity 0.049 cal/s/cm2/cmC; CTE 4.6 x 10-6/°C. CrB2 has good oxidation resistance in the same temperature regime in which B2O3 glass is stable. This glass forms as an oxidation product on the surface of the boride, protecting it from further attack. CrB2 was considered for rocket nozzles, but it does not possess enough resistance to thermal shock and oxidation at elevated temperatures. CHROMIUM BORIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

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Materials Handbook

CHROMIUM BORIDE SUPPLIERS CONTINUED

CHROMIUM NITRIDE SUPPLIERS CONTINUED

H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

CHROMIUM CARBIDES. Cr3C2. Chromium carbides are formed from ferro chrome, a powder form of iron + chromium + carbon, and are the most widely used carbides in hardfacing applications. The various forms are very hard (about 1700 HV) with a large particle size. Unlike tungsten carbide (WC), which tends to sink to the bottom of a melt, chromium carbides are evenly dispersed throughout the thickness of the deposit. Medium chromium carbide, which is typically 15% chromium/ 3.25% carbon with small additions of manganese and silicon to cleanse the steel, provides moderate abrasion resistance and good impact resistance. High chromium carbide, which is typically 28% chromium/ 4.25% carbon with small additions of manganese and silicon, provides good abrasion resistance and moderate impact resistance. Complex chromium carbide, which is typically 8% chromium/5% carbon with additions of other carbide formers (such as vanadium, columbium, tungsten, and/or molybdenum), provides excellent abrasion resistance but poor impact resistance. CHROMIUM CARBIDE SUPPLIERS

Advanced Material Specialists, Inc.

HAI ADVANCED MATERIAL SPECIALISTS INC. 1688 Sierra Madre Cir. Placentia, CA 92870 (877) 411-8971 Fax: (877) 411-8778 Email: [email protected] Website: www.haiams.com H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com CHROMIUM NITRIDE. Chromium nitride (CrN) is an extremely hard, inert, thin film coating that is applied primarily to precision metal parts. It offers greater temperature resistance than TiN and is an ideal choice in high-temperature environments. CrN also performs well in corrosive environments and in sliding wear applications. Source: Brycoat Inc., http://brycoat.com/pvd-crn.html

CHROMIUM NITRIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

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CHROMIUM OXIDE. (Chromic oxide.) Cr2O3. Mol. wt. 152; sp. gr. 5; m.p. 1990°C. Bright green crystalline powder insoluble in acids and alkalies. Derived from the mineral chromite, FeOCr2O3, which is mined in Zambia, Zimbabwe, the former USSR, Turkey, South Africa and Cuba. Prepared by heating chromium hydroxide, ammonium bichromate or potassium bichromate and sulfur. Chromium is used in ceramics mainly to impart a green color. It is most often introduced as chromium oxide or potassium dichromate. Chromium oxide for use in glass should be ground to 120-mesh and thoroughly mixed in a mill, preferably with a portion of the batch. Chromium oxide can be used in salt cake or nitrate batches and can be used in either pot or tank glass because the green is a fast color obtainable under all furnace conditions, oxidizing or reducing. The color obtained under reducing conditions, however, tends toward yellow. In high-lead glasses, the color turns yellow because of the formation of yellow lead chromate. The compounds of chromium are not very soluble in glass, and silicate of chromium is apparently formed with difficulty. If chromium oxide is not added in the correct amount and thoroughly distributed throughout the melt, large specks form in the glass. Melt heat should be kept to prevent the formation of black specks. The amount of chromium oxide required to impart a green color varies from 5-25 lb/ton of batch. The natural mineral chromite is generally used in container glass batches, and is added on the basis of contained chromium oxide. In an ordinary soda-lime batch, 10 lb of chromium oxide per ton of batch gives a medium green with somewhat yellowish cast. A pleasing blue-green glass can be obtained with 5 lb Cr2O3 and 2 lb cobalt oxide per ton of batch. Borax enhances the color and brilliance of chrome glass and helps subdue the yellowish cast. About 0.1% antimony oxide will act as a reducing agent and assist the chromium in producing a clear emerald green free from yellow. A high melting temperature, if continued for a long time, will have the same effect, making antimony unnecessary in continuous tanks. Chromium is a relatively powerful colorant, and 0.1% Cr2O3 in the batch produces a green sufficiently intense for tableware. In glazes, chromium oxide, or other chromium compounds, are commonly used to produce green colors. The oxide is generally used in raw glazes while potassium dichromate is more common in fritted glazes. An oxidizing fire must be provided to avoid development of a black color. In such glazes, zinc oxide will produce a brown color, due to the formation of zinc chromate, and high-lead glaze will form the yellow lead chromate. Tin oxide, of course, cannot be present, as it will form the chrome-tin pink. For this reason, whiting and alumina are usually used to lighten and clarify chrome green glazes. Chrome green colors are used for both underglaze and overglaze throughout the whiteware industry. The addition of 1-2% zircon opacifier is helpful as it also tends to stabilize the chrome stain and prevent brown edges. Chrome-tin pinks can be intentionally made from a calcined stain of 1-4% chromium (or equivalent dichromate), calcium, tin oxide and silica. The chrome-tin combination is created before glaze firing to assure uniform color development. Such glazes should be high in calcium or strontium, and must be free of zinc oxide to avoid development of a blue cast. Strontium, the more effective of the two, permits lower total alkaline earth, allowing maximum firing range and better control of color. Supplier listings indicate paid advertising.

2012 Edition

Chromium oxide (or dichromate) may be used to produce low-temperature (cone 010) Chinese red glazes. These are high-lead, low-alumina glazes that usually develop a somewhat crystalline texture. Chromium oxide is added to enamels to impart green colors; brilliance can be increased by adding borax or zinc oxide. Its use in ground-coat enamels or cover coats which are applied directly to iron should be avoided because it reacts with the metal, causing a condition called blistering. Chromium oxide also is one of the coloring constituents used in smelted black enamels. Here, it is added before smelting, along with iron oxide, cobalt oxide, manganese dioxide, nickel oxide and copper carbonate. Chromium oxide is a constituent of almost all black enamel stains. It’s used in amounts ranging from 12% to 35-40% in Co-Cr-Fe black stains to as high as 65% in Cu-Cr blacks. Chrome-tin pinks are used to a limited extent in dry-process clear frits, to blend with other colors in making dark maroons. They may be similarly used in wet-process opaque enamels, but some fading usually is experienced. In high-temperature enamels for AISI 300 and 400 series stainless steels, chromic oxide imparts heat resistance. A typical composition: 100 lb Solaramic 4210-2C frit, 6 lb clay, 4 oz bentonite, 21.5 lb chromic oxide, 5 gal water. CLAY. Product of the decomposition and alteration of feldspathic rocks. Consists of a mixture of particles of different sizes and widely differing physical, chemical and mineralogical properties. The nonplastic portion consists of altered and unaltered rock particles of which the most common and abundant substances are quartz, micas, feldspars, iron oxides, and calcium and magnesium carbonates. Organic matter usually is also present in greater or lesser amounts, and frequently plays an important role in determining clay properties. The essential constituents of clays are hydrated silicates of aluminum, of which there are several, but the most important and widespread are the kaolinite group, Al2O3-2SiO2-2H2O, and montmorillonite group, (Mg,Ca)O-Al2O3-5SiO2-H2O. Bentonite belongs to the montmorillonite group. Clays may be designated as residual or secondary, according to their geologic history. Residual clays are those occurring in the same location as originally formed by weathering. English china clays and North Carolina kaolin are the most important residual clays. Secondary clays are those that have been transported by water, ice or wind, and redeposited, alteration usually occurring during the transportation process typified by the middle Georgia Fall Line area. The typical clay minerals—kaolinite, montmorillonite, etc.—have microscopic plate-like structures which are believed to be chiefly responsible for their plasticity (formability) when wetted with water. Other important properties: (1) hardening when dried and permanency when fired; (2) shrinkage during drying and firing; (3) variety of colors obtainable when fired; (4) refractoriness, or resistance to softening at high temperatures; (5) heat, sound, and electrical insulation; and (6) decolorizing and clarifying action (particularly fuller’s earths, which are used for refining oils). An extremely high content of fine particles is characteristic of very plastic clays. The finest fraction, which also is quite small, contains the clay suspensoids or colloids which are responsible for the plasticity. Most of the material consists of granular matter. Too high a content of socalled clay substances can make the material excessively plastic, which renders it sticky and difficult to work. Other important factors in plasticity are the amount, size, relative proportion of sizes, shape and other characteristics of the granular material, and the amount and character of soluble salts (electrolytes) and organic material present. The fineness of a clay’s grain influences not only its

CHROMIUM OXIDE

plasticity but also such properties as drying performance, drying shrinkage, warping, and tensile, transverse and bonding strength. For example, the greater the proportion of fine material, the slower the drying rate, the greater the shrinkage, and the greater the tendency to warp and crack during this stage. Clays with a high fines content usually are mixed with coarser materials to avoid these problems. For two clays having different degrees of plasticity, the more plastic one will require more water to make it workable, and water loss during drying will be more gradual because of its more extensive capillary system. The high-plasticity clay also will shrink more and will be more likely to crack. The most important clays in the pottery industry are the ball clays and china clays (kaolin). (See CLAY, BALL and KAOLIN.) The following paragraphs focus on special-purpose clays. Enamel clays. In general, are very clean with minimal impurities, selected for their ability to hold the finely ground enamel frit particles in water suspension so they will dip and spray evenly. Clay also aids the opacity of the fired coating. Amounts of clay ranging from 2-15%, based on dry weight of frit, have been added to the mill; the usual amount, however, is about 7%. Enamel clays are usually of ball clay characteristics, although somewhat lighter in color. The well-known Vallendar clay of Germany had been used in the United States enameling industry for many years and was popular because of its exceptional freedom from carbonaceous material. Blended domestic clays also can be made satisfactory by means of purifying methods and extreme pulverization. Bentonite also is used in some plants for suspension of frit particles. (See BENTONITE.) Glaze clays. Are introduced into the glaze batch to serve as suspending and binding agents in th eunfired state, and as an intrinsic part of the finished glaze. It may be concluded that fine-grained ball clays of exceptional purity, which contain appreciable quantities of colloidal organic matter, are desirable glaze clays. Apparently, the fine clay provides suspending power and dried film strength, and its organic content prevents undue changes in slip consistency from leached out flocculating and deflocculating ions. Fine-grained china clays are used where exceptional purity is required, together with high suspending qualities. Hoever, such clays are sensitive to soluble salt effects, and usually must be modified with gum additions or deflocculants. The coarser china clays are low in film strength and suspending power but tend to release water more readily than the finer kaolins. For high film strengths, the china clays normally require binder additions. Sagger clays. Open-firing refractory clays of suitable uniformity with resistance to repeated heating and cooling. They are used wholly or in part for forming and making a refractory container, known as a sagger, in which articles are protected from dirt, furnace gases, uneven heating and thermal shock during heating in their manufacture. Clays that are plastic and used in making stoneware (heavier ceramics such as jugs, pots and other containers) are found in New York, New Jersey, Missouri, Maryland, Texas, Ohio, Minnesota, Illinois, Pennsylvania and Indiana. Many brick clays and refractory clays can also be made into stoneware. Other products made from these clays are called yelloware, artware, earthenware and terra cotta. Tableware has also been made from these clays and is classified as semiporcelain. The products may be any color, glazed or unglazed, and the body can be modified with other ceramic materials. A tensile strength of 125 psi or higher is desirable, and the clay should show low firing shrinkage. Wad clays. Low grades of fire clay, used for closing the joints between saggers when they are set up in the kiln. A wad clay should be inexpensive, should not soften so much that it will stick to the saggers, and should be free from pyrite, ferrous carbonate and other objectionable materi-

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CLAY, BALL

als. It should have good strength and low shrinkage. Ball clays are sometimes used in this application. CLAY SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com OLD HICKORY CLAY COMPANY P.O. Box 66 Hickory, KY 42051-0066 (270) 247-3042 Fax: (270) 247-1842 Email: [email protected] Website: www.oldhickoryclay.com PACIFIC CONDUIT AND CABLE, MOLDUCT TUBING AND AIRWICK 1725 Standard Ave. Glendale, CA 91201 (818) 548-7471; (323) 245-1013 Fax: (818) 548-7172 Email: [email protected] Website: www.pacificconduitandcable.com SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] CLAY, BALL. This classification originally applied to sedimentary lignite-bearing aluminum silicates that were plastic, finegrained, easily slaked in water, and would fire to a clean, cream to white color. The term “ball” was derived from the original method of mining this plastic clay in England, where CERAMIC INDUSTRY ³ January 2012

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CLAY, BALL

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Materials Handbook CLAY, BALL SUPPLIERS CONTINUED

it was cut from the bank in the form of balls weighing about 33 lb each. Later, the expression ball clay was adopted for a wide range of clays that could not be categorized as kaolins or fire clays. In the United States most ball clays are produced in Kentucky and Tennessee, with lesser amounts from California, Indiana, Mississippi, Ohio and Texas. The deposits of Kentucky and Tennessee lie in a relatively small area approximately 60 mi long by 30 mi wide running generally northwest-southeast, crossing the Kentucky-Tennessee line some 50 mi east of the Mississippi River. These lens-shaped deposits, laid down in the Upper Cretaceous era, are the products of erosion of the Appalachian Mountains by the waters of the Tennessee River. After a series of depositions and re-erosions, the fine-grained particles of kaolinite and other minerals were deposited in lagoons behind barrier beaches of the Gulf of Mexico embayment. Because of the slow movement of the streams, only the finest of sediments could be carried, which accounts for the very fine-grained nature of some ball clays. And upon reaching the lagoons, the brackish water and acids from decaying vegetation would have a pronounced flocculating effect on the fine clay particles, causing them to settle in a dense plastic mass. Geologists recognize the clay in this area as having been of several different formations. Many of the Kentucky and some of the Tennessee clays are of an earlier age and have certain characteristics, notably with respect to their associated organic material. The older formations normally contain a soft colloidal lignite, while the latter formations have the hard, massive type of lignite. The wide range of compositions for domestic ball clays is illustrated by the following analysis:

some authorities believe that minor amounts of illite and/ or mica make worthwhile contributions. Another characteristic of ball clay is its ability to be flocculated or deflocculated through the adsorption of ions from electrolytes. This phenomenon permits a wide range of viscosities in ball clay slurries or slips and serves as the basis for casting in plaster of Paris molds. Ball clay is an important raw material in ceramics for plasticity, bonding strength and refractoriness. It also is useful as an auxiliary flux. The refractory industry is a large user of ball clays, particularly in specialties such as ramming mixes, castables and plastic refractories. Since all of these specialties must be put in place, and remain firm before being matured, a binder, such as ball clay with its high plasticity and high dry strength, is used to develop the workability and dry strength of the refractory. Special refractories consisting of a high percentage of prefired grog or calcined material need plastic clay to help in forming and holding their shape during drying and firing. In some cases as little as 10-15% ball clay is used to bond 85-90% of nonplastic material. Fine-grained ball clays are used to suspend the ingredients of engobes for decorating brick and tile. Since engobes must closely match the body shrinkages of the brick and tile to which they are applied, it is necessary to adjust the percentages of frit, color, flint and ball clay to achieve this shrinkage. Its nearly-white firing characteristic enables ball clay to be used in such whiteware products as china, semivitreous whiteware and tile. The degree of plasticity exhibited by ball clay permits the formation of ware by jiggering, extrusion, pressing and casting. Very little throwing is done commercially. Amounts of ball clay commonly used in various ceramic products are: abrasives (vitreous bond), 15-30%; artware, 25-40%; electrical porcelain, 15-35%; engobes, 5-40%; floor tile, 0-25%; glazes, 5-30%; hotel china, 6-25%; porcelain enamels, 4-10%; refractories, 5-25%; saggers, 15-25%; semivitreous whiteware, 25-40%; vitreous sanitaryware, 25-38%; and wall tile, 25-40%. CLAY, BALL SUPPLIERS

The refractoriness (PCE) of ball clays normally ranges from cone 28-34. The clays fire more or less white to cream and approach vitrification in the range of c-ne 10-12. These clays slake down readily in water and, when completely dispersed with appropriate electrolytes, will exhibit a particle size from 80% <0.5 mm down to 20%. The principal clay mineral in ball clay is kaolinite; but there can be minor amounts of montmorillonite, halloysite or illite. Mica, quartz, and/or organic material such as lignite also may be present. It is the colloidal fraction of the clay minerals and the organic colloids that promote plasticity. Plasticity, one of the most important contributions made by certain ball clays, is most difficult to predict by laboratory tests. However, it can be recognized and determined qualitatively in commercial plants through comparative production trials. The presence of soft colloidal lignite, as opposed to hard massive lignite, appears to promote a type of plasticity frequently referred to as waxy plasticity. The presence of finegrained clay colloids (-0.5 mm fraction) will improve plasticity, yielding a sticky plasticity. The presence of montmorillonite is known to increase the plasticity of a clay, and

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IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com

OLD HICKORY CLAY COMPANY P.O. Box 66 Hickory, KY 42051-0066 (270) 247-3042 Fax: (270) 247-1842 Email: [email protected] Website: www.oldhickoryclay.com

January 2012 ³ WWW.CERAMICINDUSTRY.COM/MATERIALSHANDBOOK

SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com

UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] CLAY, CALCINED. Ball or china clay that has been heated until the combined water is removed and the plastic character is destroyed. CLAY, CALCINED SUPPLIERS CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com CLAY, CHINA. (See KAOLIN.) The terms kaolin and china clay are used interchangeably to describe a type of clay which fires to a white color and has a PCE of 34-35. The name kaolin comes from the two Chinese words kaoling, meaning high ridge, and was originally a local term used to describe the region from which the clay was obtained. The term kaolin was originally used in the United States to refer to certain residual clays of a white- or nearly white-burning character. In recent years, however, it has been stretched to cover certain white sedimentary clays like those obtained in South Carolina and Georgia. The present terminology differentiates between the two types of deposits by designating as primary or residual kaolins those whiteburning clays formed by the weathering, in place, of feldspathic rocks, pegmatite dikes, granites, and the like, and found in the location of the parent rock. Secondary or sedimentary kaolins are those that were formed by weathering, then carried by water and redeposited in another area. Thus, the secondary kaolins of South Carolina and Georgia were deposited in lagoons and embayments at or near the old shoreline of the Atlantic in an area later uplifted to form the Atlantic Coastal Plain. Secondary kaolins were also deposited in the lone formation in Northern California. Most of the domestic supply of residual kaolin is obtained from western North Carolina, and most of the sedimentary clay comes from Georgia, South Carolina and Northern California. The South Carolina kaolins are widely used in the refractory and elastomeric industries. Although some of the South Carolina kaolin deposits have a natuSupplier listings indicate paid advertising.

2012 Edition

CLAY, CHINA

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COBALT CARBONATE

COATINGS, CERAMIC SUPPLIERS CONTINUED rally occurring large particle size which makes them excellent casting clays, most are finer particle sized than the Georgia kaolins, and both can be fractionated into casting clays. Lone kaolins are widely used in casting sanitaryware, ceramics and refractories. Kaolin (Al2O3-2SiO2-2H2O) usually contains less than 2% alkalies and smaller quantities of iron, lime, magnesia and titanium. Because of its purity, kaolin has a high fusion point and is the most refractory of all clays. Georgia china clay is one of the most uniform kaolins to be found. Generally speaking, there are two types of Georgia-sourced kaolin, both of which are widely used for casting and other processes. One type imparts unusually high strength and plasticity, and is used for both casting and jiggering where a high degree of workability is required. The other type typically is a fractionated, controlled particle size clay that also behaves well in casting, dries uniformly and reduces cracking of ware. Both china clay and kaolin are often used in place of alumina in continuous fiberglass applications, due to their low alkali and iron contents.

CLAY, FIRE OR REFRACTORY SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com

MASON COLOR WORKS INC. 250 E. Second St., Box 76 East Liverpool, OH 43920 (330) 385-4400 Fax: (330) 385-4488 Email: [email protected] Website: www.masoncolor.com COATINGS, HIGH HEAT RESISTING. Heat-resistant coatings have the ability to absorb heat energy and reradiate that energy to a cooler substrate—a characteristic known as emissivity. The higher the emissivity, the better the coating’s performance at high temperatures and the more protection it offers to the underlying substrate(s). Such coatings are used in automotive, aerospace, military and industrial/refractory applications. COATINGS, HIGH HEAT RESISTING SUPPLIERS

CLAY, CHINA SUPPLIERS SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com CLAY, ENAMEL. (See Enamel Clays under CLAY.) CLAY, ENAMEL SUPPLIERS IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com OLD HICKORY CLAY COMPANY P.O. Box 66 Hickory, KY 42051-0066 (270) 247-3042 Fax: (270) 247-1842 Email: [email protected] Website: www.oldhickoryclay.com CLAY, ENGOBE. (See ENGOBE.)

RESCO PRODUCTS INC., CORPORATE OFFICES Two Penn Center W., Ste. 430 Pittsburgh, PA 15276 (412) 494-4491 Fax: (412) 294-1080 Email: [email protected] Website: www.rescoproducts.com CLAY, GLAZE. Fine-grained clays containing considerable amounts of colloidal organic matter, which are introduced into glaze batches as suspension and binding agents and become an integral part of the glaze during firing.

COATINGS, THERMAL SPRAY. Thermal spray coatings are typically line-of-sight processes. Coating rates are fast, and production costs can be relatively low compared to other coating methods.

CLAY, GLAZE SUPPLIERS

COATINGS, THERMAL SPRAY SUPPLIERS

IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com OLD HICKORY CLAY COMPANY P.O. Box 66 Hickory, KY 42051-0066 (270) 247-3042 Fax: (270) 247-1842 Email: [email protected] Website: www.oldhickoryclay.com

CLAY, ENGOBE SUPPLIERS IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com OLD HICKORY CLAY COMPANY P.O. Box 66 Hickory, KY 42051-0066 (270) 247-3042 Fax: (270) 247-1842 Email: [email protected] Website: www.oldhickoryclay.com CLAY, FIRE OR REFRACTORY. (See FIRECLAY.)

C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com COATINGS, CERAMIC. Inorganic, nonmetallic coatings applied over a surface and bonded in place by firing, such as a porcelain enamel or glaze. COATINGS, CERAMIC SUPPLIERS IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com

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WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com COBALT AND COBALT COMPOUNDS. Cobalt and cobalt compounds are used as colorants in glass and ceramic applications. See specific cobalt entries for additional information. COBALT CARBONATE. CoCO3. Mol. wt. 118.94; sp. gr. 4.13; insoluble in water and soluble in acids; readily decomposes upon heating. CoCO3 is prepared by adding sodium carbonate to a solution of cobaltous acetate. Cobalt carbonate is used to introduce the ceramic colorant cobalt oxide. Two preparations for black colors: 1. Ball clay, 120 parts; ochre, 120 parts; manganese dioxide, 35 parts; cobalt carbonate, 2 parts. 2. Iron chromate, 52%; nickel oxide, 9%; tin oxide, 9%; cobalt carbonate, 21%; manganese oxide, 9%.

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COBALT CARBONATE

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COBALT OXIDE

COBALT CARBONATE SUPPLIERS ARLINGTON INTERNATIONAL INC., CERAMIC RAW MATERIALS 333 W. Drake Rd., Ste. 220 Fort Collins, CO 80526 (855) 494-0244; (970) 494-0244 Fax: (970) 494-0206 Email: [email protected] COBALT CHLORIDE. CoCl2 or CoCl2·6H2O. Also known as cobaltous chloride. The hydrated form of this compound consists of red crystals and melts at 86.8°C. It is soluble in water and is used as a glass or ceramic colorant. COBALT CHROMATE. CoCO4. Mol. wt. 174.95; insoluble in water but soluble in acids and ammonium hydroxide. Prepared by the interaction of cobalt nitrate and ammonium chromate, or anhydrous cobaltous sulfate and potassium chromate. Cobalt chromate is used with aluminum oxide and zinc oxide to produce light blue stains in vitreous enamel, and also to prepare light green stains. COBALT HYDROXIDE. Co(OH)3, A material that is soluble in cold concentrated acids, insoluble in water and alcohol that is used as a precursor for cobalt salts and in catalysts. COBALT NITRATE. Co(NO3)2-6H2O. Mol. wt. 291; sp. gr. 1.8; m.p. <100°C. Soluble red crystalline material which loses half of its water of crystallization at 55°C. Prepared by the action of nitric acid on cobalt, and deliquesces in moist air. Not an important ceramic material, as the sulfate is used when a soluble salt is desired. However, cobalt nitrate is said

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to be beneficial for light-colored first-coated enamels for sheet iron. Cleaned metal is heated in a 5% solution of cobalt nitrate at about 185°F. After dipping, the piece is spun and dabbed with a cloth to remove excess solution from its edges. It is then furnace-heated for 5 min at about 570°F. The cobalt nitrate decomposes, leaving a deposit of cobalt oxide on the iron. COBALT OXIDE. Co2O3, CoO. Mol. wt. 240.5; sp. gr. 6; insoluble in water and most mineral acids but soluble in sulfuric acid. Black powder obtained by roasting cobalt ore from Zambia, Morocco, Burma and Canada to drive off arsenic and sulfur, and then separating the residue from nickel and other constituents. Cobalt oxide is used as a coloring medium in glass, pottery and enamel, and also as a decolorizer in glass and enamel. Cobalt is one of the most powerful glass coloring agents known. As little as 2 ppm produces a recognizable tint, and 200 ppm produces a blue sufficiently intense for most ware. Cobalt oxide is a very dependable colorant, producing a fine blue under all furnace conditions, oxidizing or reducing, and cannot be burned out during working of the glass. Cobalt oxide can be used in the manufacture of either pot or tank glass and can be employed with salt cake or nitrate batches. Because the oxide is so powerful, the very small amount required in some glasses is difficult to weigh accurately and incorporate uniformly throughout the batch. Hence, it is customary to use cobalt in some diluted form such as powder blue or smalt, which is a powdered glass mixture of sand, potash and 3-6% cobalt oxide. This preparation also has been called zaffre, though the term usually refers to

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Materials Handbook

the impure cobalt oxide that remains after cobalt ore has been roasted. The blue color in glass depends upon the amount of cobalt oxide introduced and the type of batch. Glasses containing borax, lead or potash instead of soda seem to give a brighter and more brilliant blue. When used in combination with other colorants such as chromium or copper, cobalt may be made to yield a blue of any desired tint from pure cobalt blue through greenish-blue and blue-green to the green of chromium. Cobalt also is used with manganese to produce purples, violets and blacks, and with barium oxide for a blue-green color. Three glass batches colored by cobalt oxide:

Cobalt oxide also is used in combination with either manganese or (usually) selenium to mask excess yellow color. Theoretically, yellow plus blue makes green which, in turn, is masked by the complementary pink of selenium. In ground-coat enamel, cobalt oxide is used to enhance adherence of the coating to the metal substrate. There are many theories as to cobalt’s function in this application. The most popular is that silicate of cobalt in the enamel frit is reduced during burning to a lower silicate and, perhaps, to metallic cobalt. Oxygen, which is given off in either case, combines with the iron and is taken into the enamel as ferrous silicate. Any metallic cobalt also combines with iron, but forms a widely distributed porous alloy which promotes adhesion. A ground coat containing cobalt oxide alone is very expensive. For this reason, either manganese oxide or nickel oxide is added to lower cost without adversely affecting tenacity of the ground coat. An increase in toughness is a side benefit. It is normally sufficient for a ground coat enamel to contain 0.23-0.47% cobalt oxide. A good cobalt-nickel combination is 0.4% Co and 0.75% Ni, while a good cobalt-manganese combination is 0.5% Co and 1.5% Mn. Cobalt oxide generally improves the quality of an enamel and decreases pinholing. With cobalt oxide in an enamel composed of 30% borax, 30% feldspar, 20% quartz, 8% soda ash, 4% soda nitrate, 6% fluorspar and 2% special oxides, both persistence and duration of reboiling increased to a maximum at 0.4-0.5% cobalt oxide and then decreased to practically zero at 2.0%. The addition of a small amount of manganese oxide helped combat reboiling. Cobalt oxide is not used in ground coats for cast iron enamels as it is of doubtful value. In the pottery industry, cobalt oxide is used to obtain blue and various shades of blue in decals, underglazes, body stains and colored glazes. In underglazes, cobalt in various forms usually is mixed and calcined with alumina and lime, and also with lead for very soft underglazes. A combination of cobalt oxide, alumina and zinc oxide usually is the form in which the stain is made up for use in a colored body. Cobalt oxide is occasionally used as a stain for bleaching the yellow color in whiteware, although the sulfate is most commonly used for this purpose. Supplier listings indicate paid advertising.

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A 0.025 equivalent of cobalt oxide gives a strong light blue and as much as 0.10 Co 3 O 4 gives a good rich cobalt blue. Stains to be used in connection with glazes which are compounded from alumina, cobalt and zinc are good at all practical firing temperatures. By using alumina as a base, lighter blues than the usual cobalt are obtained. In the case of high-cobalt content, there is a slight tendency toward a greenish tint when low-fire is given. In proper combination with MgO, SiO2 and B2O3, a beautiful red, violet, lavender or pink can be obtained. Cobalt in combination with manganese also is used in the production of black spots on terra cotta glazes. A cobalt stain made up of 10% cobalt oxide, 45% calcined alumina and 45% zinc oxide, calcined at cone 7 and ground to 200 mesh, can be added to whiteware bodies to produce very pleasing blue colors. It is said that a good coral shade is obtained by using cobalt oxide and antimony sulfate. The best blue- black stains are made with cobalt, usually a combination of cobalt, chromium and manganese oxides.

COBALT OXIDE

COLORANTS. Materials used to impart color to porcelain enamel, glazes, glass and ceramic bodies. COLORANT SUPPLIERS

MASON COLOR WORKS INC. 250 E. Second St., Box 76 East Liverpool, OH 43920 (330) 385-4400 Fax: (330) 385-4488 Email: [email protected] Website: www.masoncolor.com

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COPPER CARBONATE

most acids. Derived from the interaction of sodium carbonate with copper sulfates. Copper carbonate is used to introduce copper colors into glazes, especially in cases where instead of the blues and greens of copper oxide, it is desirable to obtain lavenders, reds and purples under reducing conditions. A brilliant red glaze is produced with 0.2-1% copper carbonate, 1% tin oxide and a reducing agent of 0.2% silicon carbide. If, in this same glaze, the SiC is omitted and the stannic oxide increased to 5-7%, a blue results, thus allowing the development of copper reds and blues or greens on the same piece. The formation of copper blue by the addition of 5.5% copper carbonate is favored by high silica. A blue glaze closely resembling the color and texture effects on Egyptian jewelry has been prepared with copper carbonate in amounts of 2.6-7.1%. This compound is superior to cuprous chloride because it’s nonvolatile. It also did not “wick out” in the body mass but instead glazed on the surface where soda was concentrated. In raw leadless glaze for pottery and tile at cone 2, 5% copper carbonate gave a turquoise green and, with other coloring materials, various shades of gray- green, blue and brown.

COBALT OXIDE SUPPLIERS ARLINGTON INTERNATIONAL INC., CERAMIC RAW MATERIALS 333 W. Drake Rd., Ste. 220 Fort Collins, CO 80526 (855) 494-0244; (970) 494-0244 Fax: (970) 494-0206 Email: [email protected] COBALT SULFATE. (Hydrous cobaltous sulfate.) CoSO4-7H2O. Mol. wt. 281; sp. gr. 1.9. Soluble red powder melts at 97°C, and loses its water of crystallization at 420°C. Derived from the action of sulfuric acid on cobaltous oxide. Cobalt sulfate is used in whiteware bodies to impart a blue or blue-white color. The sulfate is usually dissolved, added to the body slip, and then precipitated with sodium carbonate, the precipitate being the relatively insoluble cobalt carbonate. The amount of sodium carbonate used is equivalent to one-half the weight of the cobalt sulfate. The effect of as small an amount as 1 lb of cobalt sulfate per ton of batch will be noticeable. Cobalt sulfate finds further use as a decolorizer in clay bodies. Cobalt sulfate is sometimes used in decorative work where a soluble compound is needed to make solutions for spraying, as on art pottery.

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com COPPER CARBONATE. (Synthetic malachite.) CuCO3-Cu(OH)2. Mol. wt. 221.11; sp. gr. 3.9. Insoluble in cold water, decomposes in hot water, and soluble in ammonium hydroxide and

COPPER CARBONATE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL • Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

COLOR SPECKS, SIZED. Discreet particles of material formulated to provide spots of color or texture in ceramic glazes and/or bodies and usually sized through and on specific screens. These can be fritted, calcined (or sintered) at high temperatures, or produced at lower temperatures by combining conventional ceramic materials (stains, frits, raw fluxes and fillers) with thermo-fluid organic binders. These “composite” color specks are lower in density than calcined specks and tend to suspend better in glaze slurries. Color specks are usually sized in ranges between 4 mesh (4.75 mm) and 200 mesh (0.074 mm) and can be formulated for use over a wide temperature range. Almost any color in the ceramic spectrum can be produced, as can any degrees of hardness and/or “reactivity” with the surrounding glaze or body. COLOR SPECKS, SIZED SUPPLIERS TREBOL Ave. Los Angeles No. 3408 Ote. Fracc. Coyoacan Monterrey, N.L. 64510 Mexico (52) 81-8126-2300; (52) 81-8126-2321 Fax: (52) 81-8126-2303 Email: [email protected] Website: www.gtrebol.com Submit equipment definitions online at www.ceramicindustry.com/materialshandbook

CERAMIC INDUSTRY ³ January 2012

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COPPER OXIDE

COPPER OXIDE. (Cuprous oxide.) Cu2O. Mol. wt. 143.08; density 6.0 g/cm3; m.p. 1235°C. Cubic red crystals insoluble in water, soluble in HCl, NH4Cl and NH4OH. Prepared by the oxidation of copper, by the addition of bases to cuprous chloride or by the action of glucose on cupric hydroxide. (Cupric oxide or black copper oxide.) CuO. Mol. wt. 79.54; sp. gr. 6.4; decomposes at 1026°C. Insoluble in water and soluble in acids and NH4Cl. Derived by the ignition of copper carbonate or copper nitrate, copper hydrate, or oxidation of lower oxides. Both copper oxides are used in ceramics—cupric oxide is

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Materials Handbook

generally preferred in glazes and cuprous oxide in glasses. Copper ores from which these oxides are derived are mined in Arizona, Utah, Montana and Nevada in the United States; and in Africa, Chile, Canada, Russia and Japan. Cupric oxide, when used in glazes, has a wide range of color. It may be used either as the raw oxide in a raw glaze, as the raw oxide in a fritted glaze, or as part of the frit itself. It is used equally well in any of these cases, but when mixed with the frit there is a loss of color strength under certain conditions due to volatilization of the oxide, and it is not so satisfactory above cone 4 when operations are

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carried out under oxidizing conditions. The color of the glaze will depend upon these conditions: (1) amount of copper oxide in the glaze, (2) whether atmosphere is reducing or oxidizing and fast or slow, (3) RO group relation, (4) Al2O3 group relation, (5) SiO2 group relation and (6) degree of fineness of the copper oxide used. Copper oxide is the only individual pigmentary oxide in common use which in practically every combination and under ordinary conditions produces clear green colors. In combinations with tin oxide and other opacifying agents it gives turquoise or blue-greens when the glaze is alkaline. The amount of copper oxide in the glaze for light shades of green will be 0.03-0.06 equivalents, and for darker shades 0.6-1.0 equivalents. The actual amount will depend almost entirely upon composition of the RO group. In glazes containing PbO in fairly large amounts, smaller than normal amounts of copper oxide are used. Crystal effects may be produced in copper glazes by means of the firing process in conjunction with variations of the RO group. For instance, this glaze is said to give very bright crystals on a green background: 27.385 zinc oxide, 7.382 potassium nitrate, 13.700 borax, 7.200 whiting, 4.466 boric acid, 0.600 cupric oxide, 39.603 flint. This total glaze should be fritted and dextrin used to thicken it after grinding to pass 120 mesh if possible. Fire from cone 04-02 in 8.25 hr, hold at cone 02 for approximately 45 min, drop to cone 010 and hold for about 3 hr, natural cool. In producing green glazes, if the fire is oxidizing and the rate of temperature increase is the same in every case, the color will be the same. There are some copper glazes where the color will vary because of slow firing and little soaking. The best color will be obtained by a quick regular fire and little soaking. Cupric oxide is subject to color changes depending upon the six factors listed previously. CaO is not likely to affect the color of copper in a glaze. In a cone 02 glaze similar to that used on decorative ware, K2O changes the color to a yellowish tint, and when CuO is used in combination with either Na2O or PbO, the K2O should not exceed 0.15 equivalent. Copper oxide in a glaze containing barium oxide and zinc oxide gives a decidedly blue shade when combined with sodium or potassium oxide, but with lead oxide has more of a black-green color. A copper oxide glaze with calcium and magnesium oxides produces a green color very different from that produced with lead oxide. Cupric oxide is slightly affected by the use of zinc oxide in combination with lead oxide and others of the RO group. If tin oxide is incorporated in a green copper glaze of moderate intensity, the color will be changed from green to turquoise or robin’s egg blue, and will vary with the amount of tin used. The firing must remain oxidizing, and a quick fire is recommended to obtain best results. The addition of small amounts of titanium oxide (rutile) to a copper glaze with or without tin will sometimes create very beautiful, unusual effects. Generally, small brown specks and blotches will appear in the glaze by this addition. When reducing conditions prevail in the kiln, a red color is produced. In the well-known sang deboeuf and rouge flambe, the glaze should be rich in alkalies and contain but little copper oxide—only about 0.10-0.15 equivalent for dark red and 0.05-0.10 for light red tinge. This glaze, if fired to cone 5-7, reducing until 900°C and oxidizing to maturity, will give a good copper red:

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}

0.25 CaO 0.05 MgO 0.14 K2O 0.12 Na2O 0.32 PbO 0.05 ZnO 0.07 CuO

COPPER OXIDE

COPPER OXIDE SUPPLIERS 0.18 Al2O3 0.12 B2O

}

0.123 Na2O 0.734 CaO 0.143 K2O

}

0.394 Al2O3

}

0.123 SiO2 3.710 B2O3

In the enameling industry, copper is widely used in making black enamels where the black is produced in the smelter. Small quantities added to cobalt oxide, manganese dioxide and/or nickel oxide also serve to improve adherence of ground coat enamels. Copper oxide is used to make copper ruby glass. The red color is produced by precipitation of the metallic colloid by means of sodium cyanide in the batch. It is difficult to make copper ruby glass which will be transparent in thicknesses as great as 1/8 in. It is therefore generally flashed as a thin layer on a much thicker layer of colorless or opaque glass. The color ordinarily develops more rapidly and is more intense in lead glasses, and increased silica tends to reduce the rate of color development. Tin oxide and additional reducing agents such as cream of tartar are always necessary. Cuprous oxide produces blue or green glass. From 5-10 lb of oxide per ton of batch gives a desirable range of colors. Nitrate should be present during melting. Copper oxide and cobalt oxide mixed give a very delightful blue shade. When green glasses are required, copper oxide must be mixed with iron oxide, chromium oxide or both. An emerald green results from a mixture with iron oxide, and a deep green when chromium oxide is used in conjunction with copper oxide. The addition of 2-3% borax with the nitrate to the batch improves brightness.

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CRYOLITE

CORDIERITE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

2.40 SiO2 0.05 SnO2

The purple colors, which are a mixture of copper in its blue-green oxidized and red reduced forms, appear most frequently in glazes high in lime. Similar effects may be obtained in more fusible glazes by an earlier period of oxidation and by a neutral firing condition in the latter stages of firing. High lime and alumina produce purple splotches. The purple color becomes uniform if the calcium content is supplied by colemanite. Increased soda content shifts the color toward red. Red copper oxide may be used as an underglaze, being best produced by very thin sprays of copper oxide underneath a soft soda glaze. There is a tendency to leave the body and diffuse into the glaze unless both color and glaze are applied thinly. The most reliable underglazes contain at least 0.2% soda. The firing is the same as that for the red glazes. This is a reliable batch: 35% calcined clay, 25% copper oxide, 20% tin oxide, 20% following glaze.

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AMERICAN CHEMET CORPORATION P.O. Box 437 Deerfield, IL 60015-4374 (847) 948-0800 Fax: (847) 948-0811 Email: [email protected] Website: www.chemet.com COPPER SULFATE. (Blue vitriol, blue copperas.) CuSO45H2O. Mol. wt. 223.3; sp. gr. 2.284; m.p. 200°C. Poisonous blue crystalline material almost white when dehydrated. Soluble in water and alcohol. Formed by (a) the action of dilute sulfuric acid on copper or copper oxide, with evaporation and crystallization, or (b) heating copper with sulfur in the presence of air. Copper sulfate is sometimes used in the glass industry for the production of copper ruby glasses. It corresponds to 28% CuO and performs an equivalent function in the batch. (See COPPER OXIDE.) CORDIERITE. 2MgO-2Al2O3-5SiO2. Sp. gr. 2.6-2.7; hardness 7.0-7.5 Mohs. There are no known large deposits of natural cordierite, and it probably is never available for introduction in ceramic bodies. A body having the theoretical composition of cordierite may consist of 39.6% talc, 47.0% clay and 13.4% alumina. Bodies of this composition, however, have so short a vitrification range that they cannot be fired in industrial kilns. The addition of 20-30% zirconium silicate to a body of cordierite composition increases the firing range. The thermal shock properties of such bodies are excellent, even though they contain no more than 60% cordierite crystals (the balance being chiefly zirconium silicate). A wider vitrification range also has been obtained by recalcining flux ingredients, which consist chiefly of alkaline earth oxides. The dielectric losses of cordierite bodies are low, making them very suitable for high-frequency insulators. Cordierite bodies are quite difficult to glaze because of their low thermal expansion coefficient, which is hard to match in a glaze. Commercial, electronic ceramic-type cordierites range in color from off-white to light brown. Cordierite crystals can be developed in certain bodies; for example, about 30% talc in a kaolin body produces cordierite as the chief crystalline compound in the fired piece. The spalling resistance of ordinary stoneware bodies may be improved by adding magnesium oxide to promote the formation of cordierite. Cordierite porcelain is pure white and somewhat translucent, while bodies darker in color and opaque are considered stoneware. Care must be taken to assure firing at a high enough temperature to bring the reactions to completion, otherwise cristobalite will be retained in the body, preventing attainment of the desired low expansion characteristic. Instead of using talc, it also is possible to make cordierite bodies by firing magnesite with clay and quartz. Cordierite setters have been used in the firing of vitreous china dinnerware. The process appears successful but modifications were needed to overcome some warpage which appeared after five or six burns, up to cone 6. Cordierite-type compositions have been used for insulation in motors, radar and other mechanisms which operate at high temperatures. Another application is as a hightemperature flux for bonding large grains of aluminum oxide. Uses being studied include thermal barriers and abradable seals in gas turbine engines. Cordierite also is available as a fused synthetic product.

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CORNWALL STONE. (See FELDSPAR.) CORNWALL STONE SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com CRYOLITE. (Sodium fluoaluminate, sodium-aluminum fluoride.) Na3AlF6. Mol. wt. 210; m.p. 1000°C; density (room temperature) 2.95-3.00 g/cm3; density of liquid at melting point 2.1 g/cm3; hardness 2.5 Mohs; CTE 2.2 x 10-7/°C (glass) and 2.5 x 10-7/°C (enamels); water solubility (room temperature) 0.4 g/L. Other properties: index of refraction 1.34; heat of fusion 76 cal/g; transition point 565°C; composition 32.9% Na, 12.8% Al, 54.3% F; weight factors Na3AlF6 = 1.00 or Na2O = 0.4429, Al2O3 = 0.2429, F = 0.5435. Crystal is monoclinic at room temperature and changes to isometric, or possibly cubic, at elevated temperatures. Natural cryolite, which occurs in the monoclinic form, is comparatively rare. The only commercial deposit is located at Ivigtut, Greenland, where it constitutes a large bed in a granite vein in a gray gneiss. Small amounts of cryolite are found at Pike’s Peak, Colorado, and near Miask (Ilmen Mountains) in the former USSR. Pure cryolite is colorless and translucent. Refined natural cryolite is known to the ceramic industry as Kryolith, a white, finely divided powder. A typical analysis: 99.4% Na3AlF 6, 0.3% other fluorides (mostly CaF2), 0.2 SiO2, 0.07% Fe (as Fe2O3), 0.026% H2O. Important amounts of cryolite are used in the ceramic industry, the greatest consumption occurring in the manufacture of opal glass and enamels. Less widely known is cryolite’s extensive use as a filler for abrasive wheels, especially the resin- and rubber-bonded types. Another application is in flux coatings for welding rods, particularly those used to join aluminum. Cryolite has two main functions as a constituent of enamel and opal glass batches. It is a powerful flux because it has a relatively low melting point, is an excellent solvent for (or reacts strongly with) such oxides as SiO2, Al2O3 and CaO, and it forms low-melting eutectics with various compounds. Opacification is cryolite’s second function. It is a primary opacifier for opal glass and a secondary opacifier for enamels. Although there has been some disagreement concerning the identity of the crystalline or opacifying phase, glasses or enamels made from cryolite-containing batches contain NaF as a crystalline phase, or, if appreciable amounts of calcium are present, both NaF and CaF. Some crystalline form of silica also may be present. Cryolite is considered to be the most stable form of fluoride addition to glass and enamel batches, probably because of its aluminum content.

CERAMIC INDUSTRY ³ January 2012

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CRYOLITE

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DIAMOND, INDUSTRIAL

Most of the cryolite used in enamels goes into white cover-coat formulations, where it generally constitutes 5-15 wt% of the batch. However, use of cryolite is not as prevalent now that titanium enamels have replaced zircon enamels as the volume frits. Cryolite has also been used in boron- and lead-free enamels; much work on which was done in Germany in response to shortages of boron- and lead-containing materials. The cryolite contents of the B- and Pb-free enamel batches ranged from 2-13 wt%. Some jewelry enamel and ground-coat formulations also include cryolite. Cryolite is generally used either alone or with fluorspar in opal glass manufacture. Amounts in the batch vary from 4-13 wt%. In addition to acting as a flux and opacifier, cryolite aids in fining the glass and serves as an easily meltable source of Al 2O 3, which is an extremely important constituent of opal glass. The amount of cryolite added to opal glasses depends primarily on the other opacifiers present, and may be as high as 30 lb per 100 lb of batch when used alone. Other factors include: (1) type of batch used; (2) whether melting is done in a closed pot, day tank or continuous tank; (3) temperature and type of fire used in melting; (4) whether ware is to be pressed or blown; (5) whether the article is to be thick- or thin-walled; (6) if the glass is to be pressed, whether it is pressed by hand or by machine; and (7) the character and degree of opacity required. Cryolite is an efficient medium for the introduction of fluorides to glass batches. Being tied up with aluminum, the fluorine in cryolite does not as readily attack tank blocks as do many other fluorine fluxes. Cryolite, due to its high aluminum content, acts potentially in supplying alumina in an easily meltable form. High-grade illuminating ware generally has a high cryolite content, as this seems to be a good way to control light transmission. In batches where feldspar and fluorspar are used, cryolite is beneficial as it tends to intensify the opal. Cryolite opals do not burn out as easily as do fluorspar opals. Cryolite is said to be one of the best known materials for eliminating bloom often found in highly alkaline glass. It also aids durability and is thought to be the best possible means of adding alumina to the batch without introducing “cords.” As with other fluorides, cryolite increases homogeneity and aids in fining. Cryolite’s fluxing power has been used to accelerate the melting of clear glass batches, in which it also serves as a source of sodium and aluminum. Small amounts of fluorine (about 0.5%) cause a remarkable lowering of the viscosity of glass and aid in the fining operation. Fluorides were reported as fairly common fining agents in European practice with cryolite among the more common fluorine substances used. Decolorization of glass by fluorine-containing substances is attributed to the formation of iron-fluorine complexes, perhaps FeF6. Applications of cryolite to ceramic fields other than enamels or glass, such as an abrasive wheel filler and welding-rod flux constituent, have already been mentioned. Still other uses include: a mineralizer for quartzite, alumina, mullite and (with aluminum chloride) spinel; an auxiliary flux for whiteware bodies; glazes and an ingredient in special glazes for crucibles; an insolubilizer for sodium silicate coatings on roofing granules; and a mineralizer constituent of dental cements. Small amounts of cryolite are used in light bulbs to prevent and retard blackening by tungsten, and in “getter” formulations that remove trace amounts of oxygen from light bulbs.

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Materials Handbook

CRYOLITE SUPPLIERS

slips at relatively low pH (<5.0) and high solids (10% or more). DEFLOCCULANT SUPPLIERS

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com

D

EFLOCCULANTS. Any substance which, when added to a mixture of ceramic materials and water, will cause the mass to become more fluid is called a deflocculant or deflocculating agent or a dispersant. In the ceramic industry, deflocculants may consist of hydroxides of monovalent cations (such as Na +, K + or NH 4+), or salts of these cations that hydrolyze to a base such as sodium carbonate or sodium silicate. Deflocculants also consist of alkali salts of organic materials like pyrogallic acid, tannic acid, humic acid, lignosulfonic acid, and synthetic materials such as polymerized naphthalene sulfonates. Certain clays contain varying amounts and kinds of organic matter which can react with soda ash or caustic soda to form highly effective deflocculants as well. Variation in slip quality is often traceable to differences in the quantity of organic deflocculant produced from batch to batch, because of either organic variation or processing differences. The use of deflocculating agents as mentioned above can help minimize and control these differences. Synthetic materials such as the napthalene sulfonate polymers can be effectively used for these problems because of their highly consistent production controls compared to naturally derived ones. Colloidal silica is a potent “protective colloid.” This is why higher-SiO 2 sodium silicates are more effective as deflocculants for a given Na 2O content than those lower in SiO 2 . The amount of silicate required to deflocculate clay is very small, usually 0.1-0.3 wt%. Excessive amounts reduce its effectiveness. In the whitewares industry polyacylates are used often in conjunction with sodium silicate to optimize casting slip properties. The best ratio is determined by casting trails which evaluate the intergrity of the cast. The use of the polyacrylate can reduce the tendency toward a “brittle” cast, which is difficult to trim and finish properly. Sodium silicate is a very important deflocculant in plastic refractories because it can develop plasticity without the addition of too much water. Also, sodium silicate dries very hard and assists the ball clay in developing the hardness necessary for plastic refractories, ramming mixes and castables. Silicates for deflocculation are available in liquid, powder or flake forms. Alkali may be sodium, potassium or ammonium. Purchase is made by specifying the weight ratio SiO 2 :(R) 2 O, which can range from 3.75:1 to 1:1. Some nonionic colloids, notably gums and glues, also can be used to disperse clays in water. Starch is an especially effective deflocculant. The sodium salts of the polyphosphate glasses are extremely efficient deflocculants and constitute a special case because they can provide very fluid

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LIGNOTECH USA INC. 100 Grand Ave. Rothschild, WI 54474 (715) 355-3603; (908) 612-0948 Fax: (715) 355-3648 Email: [email protected] Website: www.lignotech.com SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com DEFOAMER. A chemical additive that breaks up foam in liquids, a defoamer is normally used to improve performance and alleviate other problems. (See ADDITIVES, CHEMICAL.) DEFOAMER SUPPLIERS ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com DIAMOND, INDUSTRIAL. The bulk of industrial or synthetic diamond is made by subjecting hexagonal carbon (graphite) to high pressures (approx. 5 GPa) and high temperatures (approx. 1500°C) with large special-purpose presses. By the simultaneous application of heat and pressure, hexagonal carbon can be transformed into a hard cubic form. Diamond is chemically inert to inorganic acids, but reacts upon heating with carbide forming elements such as iron, nickel, cobalt, tantalum, tungsten, titanium, vanadium, boron, chromium, zirconium, and hafnium. The thermal conductivity of diamond can be as high as five times that of copper at room temperature. In terms of electrical conductivity, diamond is an electrical insulator. Diamond is the hardest material known, but is also a brittle material, which breaks on impact. The toughness, or its inverse, the friability, can be varied considerably for industrial diamonds. The conversion from graphite to diamond is reversible at elevated temperatures (approx. 750°C in air) and can impose critical limitations on the use and fabrication of bonded diamond tools. Synthesized diamond is available in the size range from submicron to about one centimeter. Submicron and micron size diamond is used as loose abrasive in pastes and slurries for lapping and polishing applications. Depending on the needs of the application, diamond powders can be provided in several types that differ in aggressiveness or sharpness of cutting points, in shape, and in toughness. Diamond is by far the hardest and strongest of all abrasives available. As such, it is the superior abrasive of choice for grinding ceramics, glasses, concretes, natural stones, cemented carbides and other nonferrous metals. Critical in the development of an abrasive bond system for a specific area of application is the bondability of the surfaces of the abrasive. Diamonds have relative inert surSupplier listings indicate paid advertising.

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faces, and as such are retained in the grinding wheel almost solely by the mechanical strength of the bond system. Relatively weak, resilient resin bonds are used widely to grind technical ceramics. Because of the low-strength bond, even irregularly shaped, friable diamonds are lost from the surface of the wheel after undergoing only sight wear. Wheel life is relatively short. To alleviate this problem, thick metal coatings for friable diamonds were introduced. Significant advantages are, among others, that grinding heat is buffered from the degradable resin and that larger surface areas increase the bonding strength over the uncoated diamond. These advantages translate into grinding wheel life improvements, which are easily two to three times that of wheels with uncoated diamonds.

DIAMOND, INDUSTRIAL

tors. (See LEAD ZIRCONATE TITANATE and PIEZOELECTRIC COMPOSITIONS.) DIP COATINGS. Dip coating is a process where the substrate to be coated is immersed in a liquid and then withdrawn with a well-defined withdrawal speed under controlled temperature and atmospheric conditions. Vibration-free mountings and very smooth movement of the substrate is essential for dip systems. An accurate and uniform coating thickness depends on precise speed control and minimal vibration of the substrate and fluid surface. The coating thickness is mainly defined by the withdrawal speed, the solid content and the viscosity of the liquid.

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DOLOMITE

regions of the planet. The most important U.S. deposits of dolomite and dolomitic limestone are located in northwestern Ohio, New York, Connecticut, California, northwestern Pennsylvania, Missouri, Texas and Kansas. Important offshore deposits are found in England and Germany. The compositions shown in the table below are typical.

Source: “Advances in Sol-Gel Technology.” Ceramic Industry magazine, December 2001.

DIAMOND, INDUSTRIAL SUPPLIERS DIP COATING SUPPLIERS

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com DIAMOND POWDER COMPOUNDS. Diamond powders in various micrometer sizes are dispersed in a paste or carrier for finishing ceramic parts. Slurry diamond compounds that are spray-applied also are used for lapping and other finishing applications. The two major reasons for using diamond are the rapid stock removal and excellent finishes obtained. Diamond also can produce true flatness, and cause far less surface damage than other abrasives. And diamond properly used will keep dissimilar materials, one of which is a ceramic, at the same height. By selecting the proper diamond size and lap, a surface suitable for almost any application can be produced. Many diamond-finished ceramic parts are used in electronic and aerospace applications. Other diamond-finished ceramic components include seals, thread guides, drawing dies and gyro bearing races. Many of these parts have tolerances down to 0.001 micro-in. Diamond is the only abrasive capable of producing the required tolerance-surface finish combination. A diamond-finishing operation normally has as many as three steps, with a different grade of diamond used in each. Most stock removal is performed in step 1 and/or 2. The required surface finish is produced in step 2 and/or 3. In the case of seals, where the ceramic component is finished on a ceramic lap, a single grade of diamond will usually do the job. DIAMOND POWDER COMPOUND SUPPLIERS

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com DIELECTRIC POWDERS. Dielectric powders are specially formulated for electronic applications, such as ceramic capaci-

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com DISPERSANT. Material added to a solid or liquid in liquid suspensions to help separate the individual particles and increase flow and extrusion properties. (See DEFLOCCULANTS.) DISPERSANT SUPPLIERS LIGNOTECH USA INC. 100 Grand Ave. Rothschild, WI 54474 (715) 355-3603; (908) 612-0948 Fax: (715) 355-3648 Email: [email protected] Website: www.lignotech.com SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com DOLOMITE. CaMg(CO 3) 2. Sp. gr. 2.9; hardness Mohs 3.5-4.0. A rock intermediate in composition between limestone (CaCO3) and magnesite (MgCO3). True dolomite is composed of 54% CaCO3 and 46% MgCO3. Other materials containing appreciable amounts of magnesium carbonate, but less than the 46% found in true dolomite, are commonly called dolomitic limestones, and also are used in the ceramic industry. In the raw state, dolomite may be white, light buff, pink, yellow to brown and gray to blue. Its physical structure may be either crystalline or amorphous. Fired material is white. At about 1650°F, all CO2 is expelled and the material burns to dolomite lime (CaOMgO). In the presence of lower melting fluxes of acid character, dolomite frequently decomposes at even lower temperatures. Commercial deposits of dolomite are found in many

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The manufacture of dolomitic quicklime includes selection and sizing of raw material, burning or calcination to drive off the carbon dioxide, inspection of the kiln product, size gradation and removal of impurities. Vertical kilns are designed to provide several distinct steps in the burning process. The first is preheating of kiln feed, in which the cold stone is gradually brought up to calcination temperature (~1900°F) by contact with the hot gasses from the burning zone. Product is then held in the burning zone long enough for most or all of the CO2 to be driven off. (Recovery of the carbon dioxide has been tried but with little commercial success.) In another manufacturing process, preparation of rotary kiln feed includes a heavy-media separation step to remove most siliceous impurities. Rotary kilns are commonly used to produce granular sintered dolomite (dead-burned dolomite) at temperatures >1700°C. This dense product is pressed into brick which are used to line steelmaking vessels and cement kilns. The rotary kiln has become extremely important in lime processing, and is used to burn a large portion of dolomitic quicklime production. More than half of all industrial quicklime is made in rotary kilns. The rotary is particularly useful for making the “hard burned” grade of quicklime that must contain a minimum amount of unburned limestone. Dolomitic quicklime is the form of dolomite used by many glass plants. Dolomitic hydrate is made from the quicklime by adding ~20% H2O. It furnishes H2O at 600-700°F, boosting melting speed. However, little dolomitic hydrate is used in ceramics. The raw material is dry-milled and air-floated to uniform fineness for pottery applications, although a granulated form is more commonly used in the glass trade. The pottery grade is specified 100% through 100 mesh, 99.9% through 200 mesh and 99.1% min through 325 mesh. Glass plants prefer a quicklime that is 100% through 10 mesh and substantially all on 100 mesh. Davidson, Hodkin and Turner examined a series of sodamagnesia trisilicate glasses and found that small amounts of magnesia tend to produce glasses with a rapid melting rate. Large quantities of magnesia, however, result in a glass that’s hard to melt. Also, high-magnesia glasses have a viscosity much greater than that of corresponding lime glasses, and they exhibit tendencies to stringiness and cordiness not found in lime-containing glasses. When magnesia replaces lime molecularly in a soda-lime glass, meltability and workability initially improve. Thus, a glass containing 9.26% calcium oxide will have a slower melt rate and be harder to work than one with 4.43% CaO and 2.58% MgO (or any intermediate glass). Beyond this point, however, the benefits of further additions of magneCERAMIC INDUSTRY ³ January 2012

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Materials Handbook ENGOBE SUPPLIERS CONTINUED

sia decrease. When the two oxides are present in equimolecular proportions, as is the case when dolomite is used alone, the glass is not as easy to melt as lime glass and somewhat less workable. This indicates that best results are to be obtained when pure dolomite is substituted for only a part of the lime. However, northwestern Ohio dolomites are not strictly pure but contain lime and magnesia in the desirable 3:2 ratio and, therefore, they are often used as the only source of lime in commercial glass batches. Magnesia also improves the working properties of limecontaining glass and lessens the tendency toward devitrification. Jones also has noted the advantage of easier melting as magnesia replaces lime up to a certain point in soda-limesilica glasses. Beyond the relationship of about 2.6% MgO:6.5% CaO, the increased viscosity at high temperatures becomes detrimental. As MgO replaces CaO molecularly, there is a marked decrease in the setting rate near the temperature at which glassware is formed, thus increasing the working range. Annealing also is made easier, as the temperature required for annealing falls to a value lower than that for either a straight “lime” or a straight “magnesia” glass. The addition of MgO also gives a reduction in thermal expansion, and makes the glass more resistant to the corrosive effects of water. The great majority of glass container manufacturers are using only dolomite, either raw or burned, as the lime source. The ratio 4CaO:6MgO is usually used. The properties of the batch are often modified by the use of small quantities of borax to lower the melting point still further, and alumina, in the form of nepheline syenite or feldspar, is often added to improve permanence. Only in the sheet glass industry is there still a tendency to mix calcite and dolomite as liming sources. The use of dolomite is beneficial to a glass in that it is said to prevent “soda bloom” and to add luster to the ware. Dolomite has a powerful fluxing action and a glass containing dolomite is said to fine quicker than one using lime from another source. Dolomite tends to increase the modulus of rupture of glass, and it is possible to use dolomite containing as much as 30% MgCO3 in window glasses. Dolomite has often been criticized because of its relatively high iron oxide content, compared with other commercial glass batch materials. This iron content, however, offers no serious obstacle in colored glasses, and commercial producers have recently made notable strides in reducing the iron oxide content, so that more general use of dolomite in colorless glasses also is indicated. The northwestern Ohio dolomite, being very low in iron, produces, when burned, a lime of unusual whiteness which adds no color to the glass batch. Ohio dolomites commonly average 0.04-0.07% Fe2O3 in the raw state, and suppliers of burned dolomite customarily hold iron oxide content to 0.070.14%. In general, dolomite may be substituted for nearly any other type of lime flux in pottery bodies and glazes when other batch constituents are properly compensated. In ceramic bodies it promotes a glassy bond by reacting with feldspar, flint and clay in the range of cone 1-12 to form a lime glass. This property is of particular value in promoting maturing speed, especially under rapid firing schedules. The amount to be used varies with the vitrification desired and firing temperature, but the range of 0.5-8%, based on dry body weight, covers most vitreous and semivitreous bodies. Frequently a reduction in feldspar, with compensating increase in flint, seems to be possible. When dolomite is used to replace whiting, the safe firing range is widened by 1 or 2 cones. In combination with other fluxes, dolomite is effective as low as cone 03-04 and is in use as an auxiliary in those clays which carry variable amounts of alkaline earths. In such bodies, it acts as a stabilizing flux and tends to widen as well as lower the firing range.

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DOLOMITE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com DYSPROSIUM AND COMPOUNDS OF. Dysprosium has one of the highest magnetic moments of any of the rare earths (10.6 uB); however, this has not resulted in an ability to perform on its own as a practical alternative to neodymium compositions. It is now an essential additive in NdFeB production. Source: www.metall.com.cn/dy.htm

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected]

DYSPROSIUM AND COMPOUNDS OF SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com DYSPROSIUM CHLORIDE. DyCl3. Mol. wt. 268.86; shining yellow platelets (crystalline). Soluble in cold and hot water. M.p. 718°C; b.p. 1500°C. The anhydrous chloride is used for chemical vapor deposition of metal oxide thin layers. DYSPROSIUM OXIDE. Dy2O3. Mol. wt. 372.9; density 8.2 g/ cm3; cubic crystal structure. Soluble in acids and only slightly soluble in water. Dy2O3 is a rare earth available in purities ranging from 95-99.9%. Major impurities are yttrium and holmium oxides. It has seven stable isotopes ranging from 0.05-28.2%. Because of its high thermal neutron cross section (1.1 x 10-28 m2) it is of interest as a nuclear reactor control rod component. As a neutron density indicator in nuclear applications, it is used as the oxide dispersed in stainless steel, or as the disilicide, etc. Dy2O3 also is used in dielectric compositions, and as a special phosphor activator. (See RARE EARTHS.)

E

NGOBE. Ceramic coating used between a ceramic body and glaze when it is necessary to mask the color and texture of the body. The engobe must be formulated to produce a strong bond to the ceramic body and to have such physical properties as to permit satisfactory fit of the glaze. Engobes are of slip consistency and may be white or colored. The coating is applied to the ceramic body by spraying or dipping after forming and drying but before glazing. Glazes used over engobes are generally transparent, thereby permitting the color of the engobe to impart the final color effect. However, opaque glazes also are used. ENGOBE SUPPLIERS

FUSION CERAMICS INC. P.O. Box 127 Carrollton, OH 44615 (330) 627-2191 Fax: (330) 627-2082 Email: [email protected] Website: www.fusionceramics.com

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EPOXY CEMENTS AND RESINS. A flexible (usually thermosetting) resin made by copolymerization of an epoxide with another compound having two hydroxyl groups and used chiefly in coatings and adhesives. Source: www.m-w.com.

ERBIUM OXIDE. Er2O3. Mol. wt. 382.5; m.p. 2355°C; density 8.64 g/cm3. Pink powder used as a pink colorant in the manufacture of crystal glass. The addition of erbium oxide compensates for the yellow color in glass caused by Fe+3. EUROPIUM OXIDE. Eu2O3. Mol. wt. 352; m.p. 3722°F; density 7.28 g/cm3; cubic crystal structure. Used in the form of europium hexaboride, EuB6, as control rods in the liquid-metal fast breeder reactor. Europium is the activating ion in an yttrium oxysulfide for color television phosphors. The element has a red fluorescence which is the standard red for all color TVs.

F

ELDSPAR. The most common mineral in crystalline rocks. Hardness 6.0-6.5 Mohs. Usually occurs as small grains intimately associated with other minerals, but commercial deposits are obtained from pegmatites. Feldspars form a group of which the principal types are potash spar (orthoclase, microcline), soda spar (albite), lime spar (anorthite), and lime-soda spar (oligoclase, andesine, labradorite and bytownite). They are aluminum silicates of potassium, sodium and calcium. Feldspars exhibit uneven fracture, and have a vitreous to pearly luster. Colors are generally white, cream and pink, but also milky, clear, buff, brown, red, gray, green and bluish. Property ranges for the major types of feldspar are: sp. gr. 2.56-2.63; m.p. 1110-1532°C; refractive index 1.524-1.584. None of the minerals in the feldspar group is found pure. Potash feldspars always contain some albite (soda spar) and soda feldspars always contain some anorthite (lime spar). Feldspar is found in practically all igneous rocks throughout the United States and Canada. Chief commercial sources are in North Carolina, South Dakota and Georgia. European deposits are located in Norway, Sweden, Finland, France, Italy and the former USSR. Other foreign sources include Brazil, Mexico, South Africa and India. Cornwall stone is a feldspathic rock containing feldspar, quartz, and also alumina in excess of the feldspar ratio. It occurs in large deposits at Cornwall, England. General empirical formulas for the common feldspars used in ceramics are: microcline (K2O-Al2O3-6SiO2), albite (Na2O-Al2O3-6SiO2) and anorthite (CaO-Al2O3-2SiO2). Most commercial feldspars also contain iron oxide (0.040.15%) and traces of magnesia. The amount of free quartz varies considerably, with figures for commercial shipments ranging from 0.4-40.0%. Free quartz acts as a diluent in feldspar and decreases Supplier listings indicate paid advertising.

2012 Edition

FELDSPAR

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FLINT

FELDSPAR SUPPLIERS CONTINUED the fluxing power. In unburned ceramic bodies, feldspar acts as an antiplastic the same as sand does. Soda feldspar and quartz mixtures deform much more rapidly after deformation begins than do the potash feldspars or any of their mixtures with quartz. High-soda content in general indicates low deformation temperature. The fusion point of a feldspar depends upon the alkalies present, and becomes lower as soda content increases and potassium oxide content decreases. Some spars fuse as low as cone 4, others as high as cone 10, but the average is cone 8-9. With the possible exception of clay, feldspar is the most essential ceramic material in the whiteware industry. It is the universal flux used in all types of ceramic bodies, and should be ground very fine. The fluxing effect of feldspar may be noted in a whiteware body as low as cone 09. As temperature increases, the feldspar becomes more active, dissolving first the clay substance and finally the flint particles. Above cone 10, mullite begins to crystallize in the glassy matrix formed by the feldspar; at cone 12, it is present in sufficient quantities to improve ware properties. It affects practically all fired body properties, including even translucency, resonance and expansion. In some cases, the alkalinity introduced by feldspar alters the casting and working properties of pottery slips. The amounts of feldspar used in common types of pottery bodies are: sanitaryware, 25-35%; hotel china, 15-35%; chemical porcelain, 15-30%; electrical porcelain, 30-50%; whiteware, 15-30%; floor and wall tile, 10-55%. The softening range of the body decreases, and refractoriness increases with increased K2O, at the expense of NaO and CaO, in the feldspar used. With semivitreous bodies which do not contain any CaO, soda feldspar compositions mature slightly sooner than potash feldspar. When lime is added the situation is reversed. The reason: lime causes a sharp increase in the fusibility of potash feldspar but not of soda spar. The glassy content of the body produced with soda feldspar is less viscous than that produced by potash spar, and thus the soda spar bodies deform more readily. Unfortunately, there is no pronounced eutectic in the flintfeldspar system. However, approximately 20% quartz can be added to a pure potash feldspar and 10% to a pure soda spar without materially raising the melting points. Feldspars of different potash-soda ratios are sometimes interchangeably reduced. The development of leucite crystals in melting, which accounts for the high viscosity of molten feldspar, depends upon the amount of potash spar present. Translucency is best with potash spar bodies; thermal expansion is highest for bodies with high soda spar content. Ware containing soda feldspar is generally weaker (in terms of modulus of rupture) than that containing potash. High soda feldspar bodies soften at temperatures about 45°C lower than similar potash bodies. The role of feldspar in glazes is similar to that in bodies. It again is used for its fluxing action and should be ground very finely, preferably to 200 mesh, for more uniform and thorough reaction with other ingredients. Both potash and soda feldspars are used in glazes. The potash spar is desirable because it dissolves the silica more readily and makes a more durable glaze. Feldspar has been used in opal and alabaster glass for many years, but also has become widely adopted by the entire industry as an economical and dependable source of alumina. Glass spar is used in a coarse granular state, usually in the neighborhood of 20 mesh. Important chemical considerations are the alumina and iron oxide contents and the ratio between the soda and potash contents. Alumina is very beneficial to glass and is the main reason for the use of feldspar. Feldspar also is a source of alkalies and reduces the quantity of soda ash required in the batch. Iron oxide, of course, enters as an impurity and discolors the glass, so it must be held to a minimum. Glassmakers usually specify a maximum iron oxide content of 0.08% when buying feldspar.

The effects of feldspar on commercial glass batches may be summarized as: increased resistance to scratching, increased resistance to breaking due to both bending and impact, improved thermal endurance, increased chemical durability, and decreased tendency to devitrify. In view of these benefits, it is advisable to add an amount of feldspar which will leave from 1-3% alumina in the resultant glass, with 2% the approximate optimum. Some glass container manufacturers, however, are making milk and beer bottles with as much as 7-8% alumina. The effect of feldspar on the workability of glass is very similar to that of lime, although the addition of feldspar to a lime-soda glass increases the viscosity range without lowering resistance of the glass to acids, alkalies and weathering. Glass containing feldspar is especially well adapted to pressing because its skin sets quickly, thus keeping plungers from registering deeply on the ware. Feldspar does not increase the annealing temperature, but it helps improve appearance of the ware by adding brilliance. (See ALUMINA.) Feldspar is of great importance in porcelain enamels and constitutes from 25-50% of most batches. It is the principal means of introducing alumina into the batch; it adds potassium at a lower price than is possible with any other material; and it brings in silica in a form that is readily fusible. Alumina is particularly desirable in P/E batches because it has relatively high expansion, allowing good fit to the base metal. Feldspars used in enamel must become white upon burning and can contain only a very small amount of iron oxide. Excessive amounts of feldspar may produce a tendency to craze. Too high a content also may lower gloss and unduly increase refractoriness. Feldspar increases an enamel’s viscosity at any given temperature as well as its resistance to chemical action. The ease with which feldspar enters into solution during smelting depends upon its fineness; 120-140 mesh material is common in the enamel industry. Potash spar almost always is used. Soda spars frequently cause fishscaling in enamels that are entirely satisfactory when made with potash. Such impurities as garnet, hornblende, tourmaline and biotite mica cannot be tolerated. They maintain their identity throughout smelting, rise to the surface of the milled enamel and appear as black or brown specks in the finished product. Muscovite mica, a potassium-aluminum silicate, on the other hand, readily enters into solution and, therefore, is not particularly harmful. FELDSPAR SUPPLIERS

UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] FERRIC OXIDE. (See IRON OXIDE.) FERRITES. (See SPINEL.) FERROSPINEL. (See SPINEL.) FERROUS OXIDE. (See IRON OXIDE.) FILLERS, CERAMIC. Chemically inert materials used to fill holes in a surface prior to the application of a subsequent coating, or inert extenders added to a composition that do not add to or detract from the intended properties of the composition. FILLERS, CERAMIC SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] FILTRATION RATE ADDITIVE. A material added to a ceramic suspension which accelerates the rate of water removal by filtration or casting. FILTRATION RATE ADDITIVE SUPPLIERS SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com FIRECLAY. Clay containing high amounts of alumina and silica used in the production of refractory brick, kiln and furnace linings, and crucibles. FIRECLAY SUPPLIERS

IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

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CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com FLINT. SiO2. Black, gray or brown cryptocrystalline variety of quartz. Commonly occurs as nodules, either with calnareous coatings in clay or as coarse pebbles seen along a seashore where the coatings have been removed by attrition. Flint’s dark color is probably due to carbonaceous matter. The mineral breaks with a characteristic conchoidal fracture, is CERAMIC INDUSTRY ³ January 2012

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readily soluble in alkaline solution at 200°C and is soluble in fused feldspar. Flint pebbles are quarried along the coasts of Denmark, France and England. In the United States, ceramists often employ the term flint to include other siliceous minerals in addition to true flint. Sand flint, rock flint and tripoli flint (generally called potter’s flint) are various types of ground sandstone and quartzite—not true flint, though they often are used in exactly the same way. Calcined and ground flint is used in pottery to reduce shrinkage in drying and firing and to give the body a certain rigidity. Flint is employed in the manufacture of whiteware, such as fine earthenware, bone china and porcelain. In a comparison of the effects of true flint with those of three other mineral silicas on the properties of a hotel china body, it was found that the true flint body was superior in transparency. The variety of silica was found to have little effect on water absorption of the body fired to cone 10, on its linear thermal expansion to 300°C or on its impact strength. (See SILICA.) FLINT SUPPLIERS CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html FLUORIDE. Fluoride is the anion F−. It is the reduced form of fluorine when as an ion and when bonded to another element. Source: Wikipedia, http://en.wikipedia.org/wiki/Fluoride

FLUORIDE SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com FLUORSPAR. (Fluorite.) CaF2. Sp. gr. 2.9-3.3; hardness 4 Mohs; m.p. 1270-1387°C. Crystalline mineral found in a variety of colors; virtually insoluble in water but attacked by strong acids. When heated, fluorspar usually flies apart or decrepitates. Almost all American fluorspar production comes from the Kentucky-Illinois region, though Montana, Idaho, Colorado, New Mexico, Nevada, Utah and Arizona also are contributors. The United States also imports fluorspar from Mexico, Sardinia, the People’s Republic of China, South Africa and Spain. There are several grades of commercial fluorspar based on application. The ceramic grade is usually required to contain 95% CaF2 min, 3% SiO2 max, 1% CaCO3 max or 0.12% Fe2O3 max. It also must be practically free of lead, zinc and sulfur. It is usually ground to 100 mesh or finer. For certain kinds of glass, lower grades of fluorspar can be used. Practically all ceramic-grade fluorspar is a flotation product, off-white to pale gray in color. Fluorspar has two outstanding functions in enamels: (1) an opacifier for the enamel and (2) a flux for the batch. The opacity added by fluorspar is caused by the formation of fluoride crystals in the ground mass and not by bubbles of gas as formerly suggested. Fluorspar is not a strong enough opacifier to give a white enamel, but a cloudy effect is attained which decreases the amounts needed of other, more costly opacifiers. Flux tests on one sheet steel enamel showed that fluorspar acts as a flux only up to 4%, as a nonflux from 4-25% and again as a flux from 25-50%. The tests were run on an enamel containing 34.4% borax, 34.6% feldspar, 19.1% quartz, 4.3% boric acid and 3.2% alumina.

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The calcium present in fluorspar seems to combine more easily with the other ingredients of the enamel batch than does the calcium oxide of whiting (calcium carbonate). This is evident from the fact that fluorspar enamels melt at a lower temperature and become homogeneous in a shorter time than calcium carbonate enamels. The disadvantages pertinent to the use of fluorspar instead of whiting are due to two things: (1) the mineral contains fluorine and (2) it is a powerful reducing agent at the temperatures attained in the smelter. Fluorine is released during smelting and, although the virtues of fluorspar are very likely due to the energetic action of this gas, it also is active in corroding furnace linings, which shortens smelter life. The reducing action of fluorspar makes it necessary to carefully regulate the smelter to assure the presence of an oxidizing atmosphere. And, if a large amount of fluorspar is used, the amount of nitrate in the batch mix must be increased. Although some enamel compositions are said to require up to 11% fluorspar, the consensus is that amounts in excess of 3% lower acid resistance. If the smelting operation is sufficiently intense to drive off the fluorine, then acid resistance will not be impaired, but experience has shown that this point is not always reached. The nature of the enamel, its viscosity and the amounts of boric oxide and other raw materials present also are important factors. The fact that fluorspar lowers the fusion point of enamels more than does an equivalent amount of calcium carbonate indicates that it is either not completely decomposed or that the fluorine recombines in some form in which it can act as a flux. If the fluorine from the fluorspar is all driven out of the enamel, the compound resulting is probably not materially different from what is obtained when calcium carbonate is used as the source of lime. It also is important to note that the loss of silica from an ordinary enamel would be only about 3%, even if all of the fluorine were liberated as SiF4, since an enamel seldom contains more than 8% fluorspar. While this would be a decided loss in silica, it would not be sufficient to make a substantial difference in fusibility or corrosion resistance. Additions of 10% fluorspar to some enamels have been found to cause extreme crawling, which decreases as part of the fluorspar is replaced by cryolite. Fluorspar in cobalt ground coats makes the enamel more mobile and easy to work, but an excess causes a pimply surface. In cover-coat enamels, fluorspar seldom exceeds 5% of the batch because greater amounts impair color and tend to give a slightly pimply appearance. Fluorspar also has a negative effect on the color of enamels in which antimony oxide is the opacifier, imparting a bluish-green tint. This discoloration can be avoided by using antimony pentoxide (Sb4O5). The opacifying phase is Ca4F2Sb4O13 (calciumfluorantimonate). When substituted for cryolite or sodium silicofluoride, fluorspar decreases the coefficient of thermal expansion and, therefore, should be a desirable addition in some glazes to diminish or prevent crazing The chief use of fluorspar in the glass industry is as an opacifier for opal glass. In this application, it is often used with a nearly-equal amount of feldspar. A sample composition has 20 lb each of fluorspar and feldspar per 100 lb of sand. With the introduction of a little cryolite and an increase in the amount of feldspar, less fluorspar is needed. The new mix: 20 lb feldspar, 10 lb fluorspar and 3 lb cryolite per 100 lb sand. Smaller amounts of fluorspar, however, are often used in the manufacture of transparent glasses because of its beneficial fluxing action, its ability to aid glossiness and its activity as a decolorizer. Fluorspar also is valuable in optical glass batches because it has a low index of refraction and small dispersion. These same optical properties create a small demand for flawless transparent fluorspar crystals

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to correct color and spherical aberration errors in lenses for spectroscopes, microscopes and small telescopes. Small amounts of fluorspar (<1 wt.%) are used in the manufacture of continuous fiberglass. Fluorine aids in lowering viscosity and reducing liquidus, and also assists fiber formation. Generally, however, in the manufacture of glasses, as well as enamels, the fluorine content is kept as low as possible to reduce corrosion of refractories by silicon tetrafluoride gas. (Some authorities, however, question whether SiF4 is a strong corrosive.) Fluorspar has received scattered attention as a constituent in whiteware bodies and glazes, but has never been systematically evaluated in sufficient detail to permit fair appraisal of its possibilities. Fluorspar has been found to offer promise in glazes as a substitute for whiting, tending to promote more fusible glazes. During firing, fluorspar in contact with silica and clay is thought to dissociate into gaseous SiF4, a fluoride of aluminum and calcium metasilicate. The volatile fluoride may in time promote destruction of kiln refractories, which dictates the necessity for caution, particularly where firing temperatures are high. Glaze pinholing also may be a problem if firing temperatures are not properly controlled. It is probable that fluorspar and other fluorine compounds have usefulness for ceramic glazes, but their successful general application will require the development of additional information relative to advantages and limitations. As much as 15% CaF2 is used in one-fire textured glazes for floor tile. As a whiteware body constituent, fluorspar offers greatest promise as an auxiliary flux in promoting decreased porosity or lower firing temperatures. Amounts as low as 2.5% have been found effective in vitreous sanitaryware, semivitreous sanitaryware and electrical porcelain bodies. Apparently, fluorspar particle size is an important factor— coarser grades tend to promote pinholing. FLUORSPAR SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] FLUX. Any material that lowers the melting temperature of another material or mixture of materials. Fluxing substances may occur as natural impurities in a raw material. Thus, the alkali content of a clay will flux the clay. In other cases, fluxes are separate raw materials. One example is the use of feldspar to flux a mixture of clays and flint. An auxiliary flux is a third component that may make the primary flux more effective. Thus, adding 2% dolomite, talc or fluorspar to a whiteware mixture that contains 25% feldspar will produce a substantial decrease in vitrification temperature. The auxiliary constituent may be incapable of producing the same result (or too expensive to use) as the sole flux. Compounds of alkali metals (sodium, potassium and lithium) are popular fluxes for clay bodies. Compounds of alkaline-earth metals (calcium, magnesium and, to a lesser extent, barium and strontium) are common auxiliary fluxes. However, they also may be primary fluxes for such products as low-loss dielectrics. Lead and boron compounds are important fluxes for glasses, glazes and enamSupplier listings indicate paid advertising.

2012 Edition

els. And premelted glasses or frits may be used to flux clay or other bodies. The term flux also may be used to specify a low melting glass used in decorating glass products or an overglaze for clay ware. Pigments are mixed with the powdered glass flux and then applied to the object to produce a vitrifiable coating at temperatures <650°C. These glasses contain large quantities of lead oxide. A typical composition: 50% lead oxide, 36% silica, 10.8% boric oxide, 3.2% soda. FLUX SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com FORSTERITE. 2MgO-SiO2. Synthetic-fused material typically containing 56% magnesia and 43% silica. Higher purity, fine-particle-size material used extensively in electronic ceramic formulations and ceramic-metal seals because its high CTE matches that of some metals. Higher purity materials require higher maturing temperatures. FORSTERITE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] FRIT. Mixture of inorganic substances fused together in a furnace and quenched rapidly by either a water bath or water-cooled metal rolls. Frit is a complex combination of oxides. Its purpose is to render solubles and hazardous components insoluble by combining them with silica and other oxides. The fritting is done either on a continuous basis by introducing raw batch into a properly heated furnace or on a batch basis in crucibles or a rotary furnace. Frit then is used in combination with clay and possibly other suspending agents to produce a coating material for whiteware, which is applied, dried and fired to produce the glassy deposit called a glaze. Frit also is used with clay and electrolytes for coating steel, aluminum, cast iron and other metals. This coating—called porcelain enamel—is used on major household appliances, sanitaryware, cast iron and aluminum cookware and architectural panels. The coating may be applied by wet spraying or dipping. Frit is wet milled with clay and electrolytes. Drying and firing follow application. Dry application of powdered frit to pretreated metal by electrostatic spraying also is possible. Frit is milled with organic components. The drying step is eliminated. Use of frit is not only beneficial from the standpoint of stabilizing hazardous materials and controlling solubles, but it also helps develop a more uniform coating that generally fires at lower temperatures, all of which results in increased surface and color uniformity and better process control. Frit also may be used as a component for bonding grinding wheels, as a body flux to lower vitrification temperatures and as a flux for glass-decorating enamels. Frit can

FLUX

be used as a mold lubricant in continuous casting of steel, as a lubricant for metal extrusion, and as coatings for jet engine parts, rocket components, auto exhaust systems and solar heating panels. High-temperature paints and stabilizers for nuclear waste are other applications. FRIT SUPPLIERS CERADYNE VIOX INC. 6701 6th Ave. S. Seattle, WA 98108 (206) 763-2170 Fax: (206) 763-2577 Email: [email protected] Website: www.viox.com

FUSION CERAMICS INC. P.O. Box 127 Carrollton, OH 44615 (330) 627-2191 Fax: (330) 627-2082 Email: [email protected] Website: www.fusionceramics.com

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spurred a renewed interest in fuel cell technologies. Different types of fuel cells include polymer electrolyte (PEFC) or polymer exchange membrane (PEMFC), phosphoric acid (PAFC), molten carbonate (MCFC), solid oxide (SOFC), alkaline (AFC), direct methanol (DMFC) and others that are currently under development. Ceramic materials are used primarily in SOFCs but are also found to a lesser extent in MCFCs (the electrolyte in this type of fuel cell is usually a combination of alkali carbonates retained in a ceramic matrix) and PEMs. Such materials include gold, silver and platinum pastes, which are used as interconnects in SOFCs and other fuel cells; gadoliniumdoped ceria (GDC), samarium-doped ceria (SDC), scandiumdoped zirconia (ScZ), and yttria-stabilized zirconia (YSZ), which are used as electrolytes in SOFCs; graphite, which is used to form bipolar plates for PAFCs and PEMFCs; and lanthanum strontium manganite (LSM) and other lanthanum compounds, which are used as the cathode in SOFCs. Additionally, catalyst materials based on nanoscale mixtures of cerium oxide and uniformly incorporated catalytic metals are being developed for use in PEM fuel processors, and other ceramic materials are being used in the development of sensors for power generation systems based on various fuel cell types. (See also GRAPHITE, LANTHANUM STRONTIUM MANGANITE and SOLID OXIDE FUEL CELL MATERIALS.) FUEL CELL MATERIAL SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com SEM-COM CO. INC., TECHNICAL & ELECTRONIC GLASSES 1040 N. Westwood Ave. Toledo, OH 43607 (419) 537-8813 Fax: (419) 537-7054 Email: [email protected] Website: www.sem-com.com SPECIALTY GLASS INC. 305 Marlborough St. Oldsmar, FL 34677 (813) 855-5779 Fax: (813) 855-1584 Email: [email protected] Website: www.sgiglass.com FUEL CELL MATERIALS. Fuel cells are not new. In fact, the first fuel cells date back as far as the early 1800s. In 1839, Sir William Robert Grove discovered that hydrogen and oxygen could be combined to produce water and an electric current. Fuel cell development continued throughout the 19th and 20th centuries, and the 1960s saw a rapid expansion of research within the area. This was partly driven by funding from NASA, which was looking for lowweight, clean and highly efficient electricity sources for its space program. An added bonus of the hydrogen fuel cell was the production of water (and heat) that was also extremely useful within spacecraft. However, it was clear that the technology presented a number of hurdles to widespread commercialization. Within the last several years, issues such as the ongoing instability in the Middle East, the limited availability of fossil fuels and the need to protect the environment have

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PRAXAIR SPECIALTY CERAMICS 16130 Wood-Red Rd., Ste. #7 Woodinville, WA 98072 (425) 487-1769 Fax: (425) 487-1859 Email: [email protected] Website: www.praxair.com/specialtyceramics FULLERENES. Fullerenes are a recently discovered allotrope of carbon. Molecules are composed entirely of carbon, taking the form of a hollow sphere, ellipsoid or tube. Spherical fullerenes are sometimes called buckyballs, while cylindrical fullerenes are called buckytubes or nanotubes.

G

ADOLINIUM OXIDE. Gd2O3. Mol. wt. 362.5; density 7.41 g/cm3. Cubic crystals soluble in acids, only slightly soluble in water. Gd2O3 undergoes a crystal inversion at ~1300°C. The oxide has seven stable isotopes ranging from 0.20-24.9%. Its major impurities are yttrium oxide and europium oxide. A rare earth available in purities of 25-99.99%, Gd2O3 has the highest thermal neutron cross section of all the elements (46 x 10-25 m2/atom), making it a candidate for nuclear control rods. Gd2O3 also forms garnets having useful ferromagnetic properties. Applications in addition to those in the nuclear field include dielectric ceramics, microwave garnets, bubble memory substrates and as a special phosphor activator. Pressed compacts of Gd2O3 containing about 2% terbium were sintered at 1500°C. Properties: density, 7.60 g/cm3 (theoretical density = 7.64 g/cm3); modulus of rupture, 2840 psi; modulus of elasticity, 18 x 106 psi; CTE (15100°C), 10.5 x 10-6/°C.

GADOLINIUM OXIDE SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com GALLIUM. Ga. Used in metallizing of ceramics. CERAMIC INDUSTRY ³ January 2012

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GALLIUM OXIDE. Ga2O3. Mol. wt. 187.44; density 6.44 g/cm3; m.p. 1900°C. White powder insoluble in water but soluble in hot alkalis and acids. GALLIUM PHOSPHIDE. GaP. Mol. wt. 100.7. Crystallizes in zinc blende structure, lattice constant 5.447 x 10-8. Crystals are transparent with orange coloration. Prepared by melting gallium and phosphorus in a sealed silica tube and freezing slowly from one end. GaP is of some interest as a semiconductor. Its energy gap is ~1.3 eV at room temperature; infrared absorption cut-off is ~0.5 μm. GARNET. A generic term for a group of minerals consisting of silicates of calcium, magnesium, iron, manganese, boron, chrome or titanium. Sp. gr. 3.5-4.3; hardness (Mohs) 6.57.5. In the ceramic industry, garnet is used as an abrasive. GARNET SUPPLIERS

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com

GERMANIUM. Ge. At. wt. 72.6; m.p. 958.5°C; density 5.32 g/cm 3. Gray-white, brittle, metallic-appearing crystals with diamond structure. Germanium metal as well as germanium dioxide is produced in the United States, Belgium, France, Germany, the former USSR and the People’s Republic of China. The metal is prepared by reduction of GeO 2 by hydrogen, or from certain ore residues by fractional distillation of GeCl 4, its volatile tetrachloride. In addition to its use as the oxide (see GERMANIUM DIOXIDE), germanium itself is an important electronic material. Ultrahigh-purity metal, obtained by zone refining germanium reduced from high-purity oxide, is required. Impurity levels as low as 1 part in 10 10 have been obtained. Single crystals are prepared by drawing from a melt which has been doped with the required elements. As a semiconductor, germanium exhibits an energy gap of 0.75 eV and, in the case of highly perfect crystals, unusually long minority carrier lifetimes (up to 1 ms) and relatively high carrier mobilities. Its chief limitation is a low operating temperature—100°C max—imposed by the energy gap. Germanium combines semiconduction, insulation and electroluminescence in a single material. GERMANIUM DIOXIDE. GeO2. Mol. wt. 104.6; sp. gr. 4.25 (commercial grade); m.p. 1115°C; slightly soluble in water. Another form has a sp. gr. of 6.2, m.p. of 1086°C and is insoluble in water, hydrofluoric acid and ammonium hydroxide, but is slightly soluble in a strong (5N) solution of NaOH

Materials Handbook

at 100°C. Germanium dioxide (and germanium metal) is continuously produced in the United States, Belgium, France, Germany, the former USSR and the People’s Republic of China. At red heat, germanium metal will oxidize rapidly in air to GeO2. Germanous oxide (GeO) also is known, and its color and physical characteristics depend upon the method of preparation. It may be formed by the controlled reduction of GeO2 at elevated temperatures, by the hydrolysis of a dihalide or by the reduction of a germanic salt in solution. GeO2 may be used to replace silica in glass batches. It is capable of producing glasses of high refractive index. Fused GeO2 has a refractive index of 1.607; that of fused silica is 1.4588. GeO2 may be very useful for such limited applications as microscope objectives. Other properties which it may impart to glass are greater dispersion, density and expansiveness; equivalent hardness; considerably lower fusion temperatures; and higher transmissivity for infrared radiation. Germanium is especially important for military night sights, and its use in optical fibers continues to rise. The major application for high-purity material is a source of germanium crystals which are subsequently used for semiconductors. Germanium oxide complexes and solid solutions with good piezoelectric and ferroelectric properties are being investigated. GERSTLEY BORATE. Named after a former president of The Borax Co., gerstley borate (GB) was once mined near Boron, Calif., and ground by Hammill & Gillespie and Luguna Clay Co. The ore mainly contained the minerals colemanite (Ca 2B 6O 11 : 5H 2O), ulexite (NaCaB 5) 9 : 8H 2O) and hectorite. The material was used in glazes and ceramic bodies. It was also used as a bonding agent in grinding wheels, and a little was even used as a fire retardant. Although often criticized as a variable and undependable material, gerstley borate has been tremendously popular in art glazes at all temperature ranges for many decades. At the beginning of 2000, U.S. Borax stopped mining the material due to unsafe and impractical mining conditions. Since then, numerous substitutes have been developed, including Laguna Borate (supplied by Laguna Clay), Murray’s Borate (supplied by Kickwheel Pottery Supply), Cadycal (supplied by Fort Cady Minerals Corp.), Ferro Frit CC298-C (supplied by Ferro Corp.) and other boron frits, Gillespie Borate (supplied by Hammill & Gillespie), ulexite and colemanite. In April 2001, Laguna Clay learned that a limited amount of mined but unprocessed gerstley borate remained at the Gerstley mine. The company entered into an agreement to purchase all the remaining Gerstley and is milling it to the same specifications as the Gerstley sold over the past 30 years. GERSTLEY BORATE SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

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2012 Edition

GLASS

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GOLD

GLASS, POWDERED SUPPLIERS CONTINUED GLASS. Glass can be used in various forms for a number of different processes. See specific categories for additional details. GLASS ENAMEL. (Vitrifiable glass colors.) Fine-powder mixtures of low melting flux and calcined ceramic pigment, usually produced in a 9:1 flux: pigment ratio. The enamels may be mixed with suitable vehicles, applied to glass articles and fired to a smooth, hard enamel coating at temperatures below the deformation point of the ware. A glass enamel must have an expansion coefficient closely matching that of the base glass; a low enough fusion point to permit development of a good glass at a permissible temperature; and a sufficient degree of chemical resistance to materials to which the article may be exposed. The preparation of glass enamels has become a highly complex art. Enamels are compounded for maximum acid, alkali and detergent resistance. Firing temperatures range from 10001250°F. Colors and transparent colors in satin etch, matte and full gloss finishes are available. Special enamels are offered for use on Pyrex and low-coefficient glass. Applications for glass enamels include: containers, dinnerware, drinking ware, lighting goods, building exterior and interior panels, chalk boards and signs.

SPECIALTY GLASS INC. 305 Marlborough St. Oldsmar, FL 34677 (813) 855-5779 Fax: (813) 855-1584 Email: [email protected] Website: www.sgiglass.com GLASS, READY-TO-PRESS. Ready-to-press glass is a freeflowing powder with the binder system homogeneously mixed into the material. It is used to form shapes for glassto-metal seals, connectors, lighting, automotive applications, batteries, electronics and other applications.

CERADYNE VIOX INC. 6701 6th Ave. S. Seattle, WA 98108 (206) 763-2170 Fax: (206) 763-2577 Email: [email protected] Website: www.viox.com GLASS SAND. (See SILICA.) GLASS SAND SUPPLIERS

FUSION CERAMICS INC. P.O. Box 127 Carrollton, OH 44615 (330) 627-2191 Fax: (330) 627-2082 Email: [email protected] Website: www.fusionceramics.com GLASS, POWDERED. Available in a variety of compositions, powdered glass can be used to seal, fill, adhere, abrade, lubricate and coat numerous ceramic and glass products. GLASS, POWDERED SUPPLIERS

®

CERADYNE VIOX INC. 6701 6th Ave. S. Seattle, WA 98108 (206) 763-2170 Fax: (206) 763-2577 Email: [email protected] Website: www.viox.com SEM-COM CO. INC., TECHNICAL & ELECTRONIC GLASSES 1040 N. Westwood Ave. Toledo, OH 43607 (419) 537-8813 Fax: (419) 537-7054 Email: [email protected] Website: www.sem-com.com

FUSION CERAMICS INC. P.O. Box 127 Carrollton, OH 44615 (330) 627-2191 Fax: (330) 627-2082 Email: [email protected] Website: www.fusionceramics.com

GLASS, READY-TO-PRESS SUPPLIERS

GLASS ENAMEL SUPPLIERS CERADYNE VIOX INC. 6701 6th Ave. S. Seattle, WA 98108 (206) 763-2170 Fax: (206) 763-2577 Email: [email protected] Website: www.viox.com

GLAZE SUPPLIERS

IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website:www.imerys-ceramics.com GLAZE STAINS. Prepared calcined ceramic pigments which, when mixed with a glaze before it is applied to the ware, give a uniform color throughout the glaze layer. Most glaze stains function as pigments. Some remain as precipitates, while others are dissolved in the fired glaze. Color range of glaze stains is very wide at lower fires. At cone 8 or higher, many glaze stains become unstable and the range of obtainable colors narrows. GLAZE STAIN SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] GLAZE. Generally, thin silicate mixtures fused on the surface of a ceramic body. They are glasses in their physical and chemical nature: hard, slightly or completely insoluble excepting in strong acids or bases, and impermeable to gases and liquids. Also, like glasses, they are not definite chemical compounds. Instead, they are complex mixtures sometimes described as undercooled solutions, because many of their properties are analogous to those of ordinary solutions. Glazes may be more or less lustrous, with a highly reflective or glossy surface. However, by dispersing selected crystals in the glaze, a matte finish can be produced. All gradations of glossiness or matteness may be observed. Crystals also may be dispersed in a glaze to provide opacity or color. Glazes may be colored, colorless, transparent, translucent or opaque. Regardless of its appearance, a glaze (or similar coating) is used to make ceramic body impermeable to liquids and gases and/or to provide decoration. Designing a glaze to “fit” a given body is a complex problem involving such variables as temperature, maturity, expansion under temperature, viscosity and mechanical strength.

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MASON COLOR WORKS INC. 250 E. Second St., Box 76 East Liverpool, OH 43920 (330) 385-4400 Fax: (330) 385-4488 Email: [email protected] Website: www.masoncolor.com GOLD. Au. At. wt. 197; sp. gr. 19.3; m.p. 1064.4°C; boiling point 2600°C. Precious metal soluble in aqua regia but insoluble in other mineral acids. The most malleable and ductile of the metals, gold also retains its luster indefinitely—it neither corrodes nor tarnishes, and is unaffected by exposure to air or water. Gold is mined on every continent except Antarctica. The major gold-producing countries (in order of production) are: South Africa, the former USSR, Canada, the People’s Republic of China and the United States. Gold has been used to decorate ceramics and glass since the times of the early Egyptian and Chinese civilizations. But it is only in this century, with the development of “liquid gold” technology, that gold-decorated china and glassware became available to all, and not just the wealthy and powerful. Two principle types of liquid golds are available for decorating glass and ceramics: liquid bright and liquid burnish golds. The most brilliant and popular are the liquid bright golds, which basically are solutions of organic compounds in organic solvents. They normally contain small, but essential, additions of compounds of rhodium and of such base metals as bismuth, chromium, vanadium, silicon and tin. The most commonly used commercial grades contain 8-10% Au. A good product will have a working temperature range of 60-100°F without loss of flow or spread. Fired bright-gold films up to 2000 angstroms thick are readily produced. Glass or glazed ceramic ware can be decorated effectively for a gold cost ranging upward from a few cents CERAMIC INDUSTRY ³ January 2012

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GROG

per square inch, depending on bright gold grade (% Au) and method of application. Liquid bright golds can be applied by brushing, screen printing, spraying, machine banding, roller topping, rubber stamping, decal transfer and silicone pad printing. Each method requires a specially prepared product with suitable rheological properties. Decorated ware must be fired at high temperatures: 1050-1200°F on glass, depending on glass composition and hardness, or 1250-1550°F on glazed ceramics, depending on glaze composition and hardness. During firing, solvents in the liquid gold are volatized, any remaining organics are carbonized and the organometallics are reduced to metal, resulting in a thin, continuous, adherent, mirror-bright film of nearly pure gold (~22 carat) on the ware. Bright Gold on Glass. Since the development of one-fire bright golds, many applications have been found by glass manufacturers and decorators. Cosmetic containers, nonreturnable beverage containers and many varieties of glass tableware are now decorated with bright gold. Automatic screen printing and machine banding are widely used, although hand banding is still a basic decorating technique. Soda-lime glass is fired at 1100°F while borosilicate glass is fired as high as 1300°F. The actual peak temperature used is dictated by the composition and thickness of the glass, with firing just short of the distortion point being necessary to obtain the best adherence. Ventilation during firing is more critical with bright gold than with ceramic colors. A forced air exhaust in the lehr’s preheat section is typically used to remove combustion products. It is common practice to fire gold and ceramic colors in the same lehr. In fact, many decorated articles combine gold and ceramic colors. Burnish golds in paste or more fluid liquid form are suspensions of gold powders and solid fluxes in suitable organic vehicles. In liquid form, they are usually mixed with liquid bright golds to achieve varying degrees of brilliance. They are formulated in various consistencies for different methods of application, from hand brushing to machine banding and screen printing. Various shades of yellowness of the fired film also are available. Buffing or burnishing of the fired film with a fiberglass brush or fine sea sand is required. Liquid bright golds are supplied with precious metal contents of 6-15% Au, with the average in the 8-10% range. Burnish golds contain 15-40% Au, with the average in the 15-24% range. The actual gold content is tailored to the application. GOLD CHLORIDE. AuCl3. Mol. wt. 304; sp. gr. 3.9. Soluble yellow crystals decompose at 254°C and sublime at 265°C. Gold chloride is prepared by heating chloroauric acid to its decomposition point. A mixture of gold chloride and stannous and stannic chlorides gives the well-known color Purple of Cassius. The shade or tint of purple depends on the gold:tin ratio. Proportions of 1:10 will give a maroon, 1:5 a rose and 1:4 a light purple. With a higher percentage of gold, the purple changes to a liver-brown. With the addition of silver chloride or carbonate, the color tends toward red. Purple of Cassius loses some of its quality upon heating above 800°C, but it is sometimes used if no other color is available. If mixed with a white body, it produces a dirty violet and is then stable up to cone 16. Purple of Cassius has been used to make ruby glass. The cooled glass is colorless: the red is developed by reheating. Further heating causes the red to change to blue and then to brown. Because the ruby color is so intense, it is usually applied as a “flashed” coating on the outside of a colorless glass during the working process. Glasses high in potash are essential for best results. The cost of this glass usually excludes it from all products except luxury ware.

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Other Purple of Cassius applications include decorating pottery and as a colorant for enamels. GRAIN, REFRACTORY. Material particles classified into predetermined sizes for use in refractory applications. (See also ABRASIVES; ALUMINA, FUSED; ALUMINUM OXIDE; BORON CARBIDE; and SILICON CARBIDE.) GRAIN, REFRACTORY SUPPLIERS CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html GRAPHITE. (Carbon.) C. A natural and synthetic mineral. Graphite sublimes at 3500°C and 1 atm.; m.p. ~3700°C and 816 atm. Graphite will begin to oxidize at temperatures as low as 335°C, and oxidizes readily above 800°C. Ceramic coatings have been developed to reduce this oxidation characteristic. Natural graphite is widely distributed throughout the world with the best sources being Ceylon, the People’s Republic of China, Brazil, Canada, Germany, Madagascar, Mexico and Korea. Graphites have a sp. gr. of 2.1-2.5 as mined, but purified material is close to the theoretical value of 2.26. Ideally, graphite should behave as a metalloid in two directions and a ceramic in the third. Thus, for flake graphite or other polycrystalline graphites in which crystals are well oriented, the thermal and electrical conductivities are high in two directions and low in the other. However, such material as Ceylon chunk graphite consists of disordered crystals and has nearly isotropic properties. Natural graphites are unctuous and soft (hardness 0.51.5 Mohs), burn slowly, are chemically inert and have a sublimation temperature >3500°C. Graphite has excellent weathering properties, is hydrophobic, and tends to form water in oil-type emulsions. It is used in clay-bonded refractories and may be glazed to prevent oxidation. Synthetic graphite can be made in large pieces with properties which can be varied over wide ranges. Sp. gr. varies from 1.2-2.0 for normal commercial graphites and from 1.2-2.26 for pyrolytic graphites. Thermal conductivity for normal commercial graphite at room temperature is about 0.3 cal/(cm•s•C). For pyrolytic graphites, the values in two directions can vary over the 5.0-0.5 cal/(cms•C) range, and in the third, from 0.0040.008 cal/(cm•s•C). Electrical resistivity for commercial graphite is 700 μOhm-cm at room temperature. In the high-conductivity directions, the resistivity of pyrolytic graphite can be varied from 60-4000 μOhm-cm; in the high-resistance direction, from 0.6-0.1 Ohm-cm. The tensile strength of commercial graphite increases with temperature from ~1700 psi at room temperature to 3400 psi at 2450°C. Pyrolytic graphite has an ultimate tensile strength in the strong orientations of 20,000 psi at room temperature and 60,000 psi at 2750°C. In the weak orientation, strength is 1500 psi from room temperature to 1000°C. Graphite, which is found in the mineral form, is said to be “nature’s best refractory.” Desirable properties of graphite refractories include high thermal conductivity, high electrical conductivity, low thermal expansion, high resistance to molten metal and flux attack, excellent heat shock resistance, increased strength at high temperatures, resistance to wetting by molten substances and high refractoriness. All types of mineral graphite are used in refractories. Madagascar flake, for example, is used almost exclusively in crucibles. Mexican, Ceylon and flake dusts are used for

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the foundry facings that prevent mold sand from adhering to metal castings. Other graphite-containing refractories include stopper heads and nozzles, retorts, tubes, rods and stirrers, brick, slabs and special shapes, refractory cements, and plastic linings for ladles, runners, etc. Mineral graphite of the microcrystalline type, often referred to as amorphous graphite, is found in most of the ramming mixes used by the steel industry. Graphite is mixed with fireclay to produce plastic patch material, unburned brick and mortar. It also is used with high-alumina clay for plastic material and unburned high-alumina brick. The amount of graphite used in various refractories varies from 10-60%, except in foundry facings where pure graphite may be used. Graphite also is used to moderate high-velocity neutrons in nuclear energy applications. It boasts a low neutroncapture cross section. Manufactured forms of graphite, referred to as synthetic graphite, resist attack by all materials except oxidants. It is unreactive with many metals (zinc, aluminum, magnesium, copper and their alloys) and metal-producing slags at their melting points. A special form of synthetic graphite, pyrolytic graphite is unusually nonreactive and can be made into long-lasting crucibles for molten silicon and many of the more reactive elements. Average threshold oxidation temperatures for most commercial graphites are 400°C in air, 700°C in steam and 900°C in CO2. Corresponding values for pyrolytic graphite are ~200°C higher. Graphite is well known for its lubricity, and is an important ingredient in most lubricants for glass molds, particularly for the blank molds used in container manufacturing. Because of its outstanding high-temperature strength, graphite is often chosen for molds used in hot pressing of advanced ceramics. It is also outstanding for the ultrahigh temperatures encountered in guided missiles and electric arc furnaces. GRAPHITE SUPPLIERS SUPERIOR GRAPHITE CO., INDUSTRIAL PRODUCTS 10 S. Riverside Plaza Chicago, IL 60606 (312) 559-2999; (630) 841-0099 Fax: (312) 559-9064 Email: [email protected] Website: www.superiorgraphite.com GRIT. Coarse-grained sharp angular granules of sand, garnet, alumina or other synthetic substances used mainly as an abrasive. GROG. Originally, naturally occurring calcined fireclay fired by volcanic action and ready for sizing after mining. As grog usage increased, however, fireclay was calcined in lump form to be ground for grog. Today, grog is usually produced from new and used refractory rejects, such as firebrick, shapes, pottery and other burned ware. It is introduced into ceramic compositions along with raw constituents to improve the physical properties of stoneware, saggers, fireclay, sanitaryware, acidproof ware, vitreous china sanitaryware, refractories, high-temperature porcelain, terra cotta and sewer pipe. The amount of grog used ranges from 5% in some formed refractories to 70% in some castables or mortars. Grog is produced in many sizes, typically from 8 mesh and finer to 48 mesh and finer. Split sizes often are used to obtain desired density in formed refractories. Special types of grog are manufactured for ceramic applications. (Calcined clay is generally not classified as grog even though, strictly speaking, it qualifies.) Grinding can be expensive if media are not chosen to Supplier listings indicate paid advertising.

2012 Edition

stand up to grog’s abrasiveness. However, the benefits of using grog generally offset the added cost and higher wear rates. GROG SUPPLIERS CHRISTY MINERALS CO. P.O. Box 159 High Hill, MO 63350 (636) 585-2214 Fax: (636) 585-2220 Email: [email protected] Website: www.christyco.com/mineral.html

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com MARYLAND REFRACTORIES CO., A STEEL VALLEY CO. P.O. Box 267 Irondale, OH 43932 (330) 532-9845 Fax: (330) 532-3224 Website: www.mrcgrog.com GYPSUM. (See PLASTER OF PARIS.) GYPSUM SUPPLIERS ALLIED CUSTOM GYPSUM 1550 Double Dr. Norman, OK 73069 (405) 366-9500 Fax: (405) 366-9515 Email: [email protected] Website: www.alliedcustomgypsum.com GYPSUM CEMENTS. A group of cements and plasters made principally from gypsum (calcium sulfate). (See also CEMENT, GYPSUM.)

GROG

HAFNIUM OXIDE, HIGH-PURITY. Hafnium oxide with purity levels of 98-99.99%. (See HAFNIUM OXIDE.) HALLOYSITE. Al2Si2O5(OH)4. Halloysite is a 1:1 aluminosilicate clay mineral typically formed by hydrothermal alteration of alumino-silicate minerals. HALLOYSITE SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

H

AFNIUM OXIDE. HfO2. M.p. 2790°C; softening temperatures (predicted) 1100-1500°C; density 9.7 g/ cm3; CTE (250-1300°C) 5.8 x 10-6/°C. White powder when pure, undergoes monoclinic transition at 1700°C. Chemically resistant but reacts with hydroxides at elevated temperatures. HfO2 is usually present in amounts of 0.5-2% in zirconium ores, and is in solid solution in commercial zirconia. In the commercial ZrO2 used in refractories, the HfO2 content is beneficial because of its lower thermal expansion, higher inversion temperature and smaller volume change during inversion. It is stabilized by CaO additions to the zirconia refractory just as the zirconia is stabilized. Although relatively scarce and difficult to separate from zirconia, it has use as a super-refractory.

IRON

sq to megohms per square can be tailored. The screen printed mix consists of high-purity indium oxide, dopants and borosilicate glass flux. Firing temperature: 900-1000°C. Temperature coefficients of resistivity of such systems have been measured at <500 ppm/C from room temperature to 100°C. INGOT, ELECTRON BEAM PHYSICAL VAPOR DEPOSITION. An ingot is a mass of material that has been cast in a shape convenient for processing, transportation and storage. During the electron beam physical vapor deposition (EBPVD) process, the material in the ingot is melted, evaporated and deposited onto a substrate. INGOT, ELECTRON BEAM PHYSICAL VAPOR DEPOSITION SUPPLIERS PHOENIX COATING RESOURCES INC. P.O. Box 1439, 2377 S. R. 37 S. Mulberry, FL 33860-1439 (863) 425-1430 Fax: (863) 425-1524 Email: [email protected] Website: www.phoenixcoatingresources.com

HEAVY SPAR. (See BARYTES.) HEMATITE. An iron ore. (See IRON OXIDE.) HEXABORON SILICIDE. B6Si. Free-flowing microcrystalline powder containing 70% B. Material is dimensionally stable and chemically inactive in air to at least 2500°F. Used as a neutron control source in nuclear energy applications. Also has potential as a machinable ceramic similar to hotpressed boron nitride. HEXABORON SILICIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

GYPSUM CEMENT SUPPLIERS ALLIED CUSTOM GYPSUM 1550 Double Dr. Norman, OK 73069 (405) 366-9500 Fax: (405) 366-9515 Email: [email protected] Website: www.alliedcustomgypsum.com

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HOLMIUM OXIDE. Ho2O3. Mol. wt. 377.9; m.p. 2360°C; cubic structure. Rare-earth oxide soluble in acids, slightly soluble in water. Available in purities of 99% and 99.9%, and in buff-colored granules or powder. Impurities are dysprosium oxide and erbium oxide. Is used in special refractories.

I

NDIUM. Indium was discovered by Reich and Richter in 1863 and was named after the brilliant indigo line it displays in its atomic spectrum. Indium is most often found with zinc minerals and is never found as a free element. Commercially, it is found as a by-product of zinc, lead iron and copper ores. It is isolated by the electrolysis of indium salts in water. Indium is very soft, silvery white in appearance, has a brilliant luster, emits a high-pitched cry similar to gallium when bent, is wetting towards glass, and is stable in air and water but dissolves in acids. See specific compound listings for additional information.

INKS, INORGANIC. Inorganic inks are made from mineral sources, typically glass powder and an inorganic pigment. The ink melts onto the substrate by heat-treating at high temperatures (500-600°C). Inorganic ink has semipermanent durability and typically does not disfigure unless the coated substrate is broken. Sources: http://okuno.co.jp/okuno_e/inorganic/in_top.html and http://www. ferro.com/-Our+Products/Glass/Technical+Information/Glossary/.

INKS, ORGANIC. Inks made from raw materials of animal or vegetable origin, not elemental (mineral), although in some cases mineral pigments may be used. Source: http://www.ferro.com/Our+Products/Glass/Technical+Information/ Glossary/.

INKS, ORGANIC SUPPLIERS POLYMER INNOVATIONS, INC. 2426 Cades Way Vista, CA 92081 (760) 598-0500 Fax: (760) 727-3127 Email: [email protected] Website: www.polymerinnovations.com INKS, ULTRAVIOLET. UV inks are formulated to dry quickly with ultraviolet light. The inks, which provide hard, dry, highly crosslinked print resistant to rubbing and marking, can be used in virtually every printing process and market. Source: Zilinskas, Dwight, “Introducing UV Inks.” http://americanprinter.com.

INKS, ULTRAVIOLET SUPPLIERS

RUCO USA INC. 915 N. Central Ave. Wood Dale, IL 60191 (847) 233-8002; (866) 373-7912 Fax: (847) 440-9148 Email: [email protected] Website: www.rucousa.com

Source: AZoM.com.

IRIDIUM OXIDE. IrO2. A black pigment with a rutile structure.

INDIUM OXIDE. In2O3. Mol. wt. 277.64; sp. gr. 7.179; m.p. 1910°C. An n-type semiconductor finding use as a resistive element in integrated circuits. Resistivity values from 100 ohm/

IRON. Fe. Practically all sheet steel used in porcelain enameling is made in basic oxygen or open hearth furnaces. Molten metal is cast into ingots, hot rolled on continuous

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IRON

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KAOLIN

tandem mills, descaled, cold reduced on continuous tandem mills, then annealed or normalized and finally given a light skin pass. There are three types of sheet steel products used for porcelain enameling: (1) regular low-carbon cold-rolled steel, (2) low-metalloid enameling iron and (3) very-lowcarbon decarburized steel. The sulfur content of cast iron for enameling should be low. High sulfur iron is brittle, does not cast well and tends to contain many slag holes. In the hollowware industry, pure iron is not used because higher ductility is needed in the base metal. The base metal most suitable for hollowware is a low-carbon steel with good drawing properties. A typical composition is 0.05-0.1% C, 0.25-0.50% Mn. Its tensile strength is higher than that of flatware enameling iron. Many other porcelain-enameled products are produced with a cast iron base, particularly sanitaryware, lavatories, undertaker’s slabs and scale bases. Cast irons for enameling fall in this general composition range: 2.0-2.6% Si, 0.300.85% P, 0.3-0.6% Mn, 0.05-0.10% S, 3.2-3.6% total C. Gray cast iron is universally used in the glass industry for molds. A suitable iron must be sufficiently closegrained so that it can be machined and polished to a highquality surface. This requirement is generally met by casting the iron against a chill to rapidly cool or quench that portion of the mold that will be in contact with the hot glass. Rapid cooling produces a dense iron with a high dispersion of fine graphite of rosette or nest form, which makes a high polish possible. This microstructural feature is also thought to help prevent sticking of the glass to the mold surface. IRON OXIDE. FeO, ferrous oxide; Fe2O3, ferric oxide or hematite; and Fe3O4, ferrous ferric oxide or magnetite. The manipulation of the magnetic properties of Fe3O4 by combination with other metallic oxides, ceramic processing and sintering constitutes the basis of the ferrite industry. Ferrites are a class of magnetic ceramics having the spinel cubic structure. Their general formula is MeFe2O4, where Me may represent Zn, Cd, Cu, Mg, Co, Ni, Mn, Fe or a mixture of these or other ions. (Permanent magnet ceramics known as “type M” or magnetoplumbites with hexagonal crystal structure also are included in this class.) Magnetite (Fe3O4) is the parent of all ferrospinels, with all or part of the ferrous ions (Fe2+) replaced by one or more divalent cations, such as Mg, Cu, Mn, Co, Ni, Cd and Zn. The last two form “normal” spinels and are nonmagnetic; however, they are important for enhancing magnetic properties of magnetic spinels. Magnetic ferrospinels have the “inverse” cation arrangement or some variation between that and the normal arrangement, depending upon the particular compound and its heat treatment. Ferrites are generally prepared by reactions between component oxides and are processed by standard ceramic techniques. Pigment manufacturers and chemical suppliers offer some of the ferrite powders; most component manufacturers prefer to calcine their own. The special care required to maintain the high purity of the material and the skill needed to achieve the desired homogeneity in the final product make it necessary to control all steps closely from the initial oxides to the sintered piece. Useful electrical and magnetic properties can be varied widely by processing; therefore, no tabulation of these properties can be regarded as representative. In addition, the industrial products are rather complex combinations, which vary markedly from the ideal ferrospinels discussed above. Their greatest utility has come in replacing less efficient materials in electronic and microwave circuits operating at high frequencies. Iron oxides for ferrites are produced by calcining the acicular types or are made synthetically. Synthetic iron oxides of the type manufactured for use as paint pigments are also suitable for use in ferrites.

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Materials Handbook

Iron oxides are also commonly used in whiteware glazes and body stains for producing tan and brown colors. A variety of colors ranging from greenish-brown to dark brown, with light brown crystals, will be produced by adding 2.1% Fe2O3 to this crystal glaze composition: 35.0% feldspar, 12.5% whiting, 2.5% zinc oxide, 1.5% barium carbonate, 14.5% magnesium carbonate, 8.6% ball clay, 25.5% flint. It is said that a very desirable pink vitrified body can be obtained by using 1% iron oxide in a stain that also contains 85% calcined alumina, 5% calcium sulfate and 9% flint. Iron oxide is probably most often used in glazes to tone or alter the shades produced by other colorants, such as cobalt, copper and uranium. A regular porcelain body containing 4-10% precipitated iron hydroxide burns red to dark red at cone 5. Uniform gray shades can be made by precipitating 2% iron hydroxide in a porcelain body and burning under carefully controlled firing conditions. In high-temperature (cone 11-13) matte glazes, iron oxide with titanium will produce fairly bright shades of red. Such a glaze might have this composition: 50% feldspar, 13% flint, 13% china clay, 24% whiting, 9% light rutile, 5% iron oxide. In porcelain enameling, iron oxide in the form of scale on the base metal will cause blisters and shivering. Iron oxide is responsible for the mottling of certain hollowware enamel. Iron is not added for this purpose, however, but is produced on the steel itself by the action of an acid salt which causes rusting. A carbonized layer of iron oxide is sometimes formed on enameling iron sheets by over-pickling. This material, which is easily overlooked, causes a great number of severe defects as soon as the ware is fired. IRON OXIDE, MICACEOUS. Also commonly referred to as MIO or MIOX (although the latter is a registered trade name of Kärntner Montanindustrie [KMI] in Austria), micaceous iron oxide is a unique, lamellar-shaped (micaceous or flat) particle that is used for several applications. In paint, it forms a “barrier” or “shield” effect to protect against moisture, ultraviolet light, abrasion resistance, chalking reduction and other external factors. With a melting point of greater than 1500ºC, micaceous iron oxide can both absorb and reflect heat. Coatings incorporating this material protect structures subjected to high temperatures. Additionally, the unique shape of the particle gives off a “glitter” or metallic sheen that is used for aesthetic purposes in ceramics, plastics and architectural coatings. Recently introduced grades of micaceous iron oxide include micronized grades (20 to 100 microns) and a submicronized grade (98% below 1 micron). However, it is the coarser pigments that find use in ceramics—particularly in tile, where they are increasingly used for their decorative effects. Many European decorators have begun specifically requesting “MIOX”-based ceramic tile because of their unique look. IRON OXIDE, MICACEOUS SUPPLIERS

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com

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K

AOLIN. (China clay.) Al2O3-2SiO2-2H2O). The terms kaolin and china clay are used interchangeably to describe a type of clay which fires to a white color and has a PCE of 34-35. The name kaolin comes from the two Chinese words kao-ling, meaning high ridge, and was originally a local term used to describe the region from which the clay was obtained. The term kaolin was originally used in the United States to refer to certain residual clays of a white- or nearly white-burning character. In recent years, however, it has been stretched to cover certain white sedimentary clays like those obtained in South Carolina and Georgia. The present terminology differentiates between the two types of deposits by designating as primary or residual kaolins those white-burning clays formed by the weathering, in place, of feldspathic rocks, pegmatite dikes, granites, and the like, and found in the location of the parent rock. Secondary or sedimentary kaolins are those that were formed by weathering, then carried by water and redeposited in another area. Thus, the secondary kaolins of South Carolina and Georgia were deposited in lagoons and embayments at or near the old shoreline of the Atlantic in an area later uplifted to form the Atlantic Coastal Plain. Most of the domestic supply of residual kaolin is obtained from western North Carolina, and most of the sedimentary clay comes from Georgia and South Carolina. The South Carolina kaolins are widely used in the refractory and elastomeric industries. Although some of the South Carolina kaolin deposits have a naturally occurring large particle size which makes them excellent casting clays, most are finer particle sized than the Georgia kaolins and both can be fractionated into casting clays. Kaolin usually contains less than 2% alkalies and smaller quantities of iron, lime, magnesia and titanium. Because of its purity, kaolin has a high fusion point and is the most refractory of all clays. Lone kaolins are widely used in casting sanitaryware, ceramics and refractories. Georgia china clay is one of the most uniform kaolins to be found. Generally speaking, there are two types of Georgia-sourced kaolin, both of which are widely used for casting and other processes. One type imparts unusually high strength and plasticity, and is used for both casting and jiggering where a high degree of workability is required. The other type typically is a fractionated, controlled particle size clay that also behaves well in casting, dries uniformly and reduces cracking of ware. Fired color is an important secondary parameter for Georgia kaolin, also due to its low Fe2O3 and TiO2 content.

KAOLIN SUPPLIERS ACTIVE MINERALS INTERNATIONAL LLC, DISTRIBUTION 6 N. Park Dr., Ste. 105 Hunt Valley, MD 21030 (410) 825-2920; (800) 233-4482 Fax: (815) 333-2997 Website: www.activeminerals.com

IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com

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2012 Edition

KAOLIN

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KYANITE

KAOLIN SUPPLIERS CONTINUED OLD HICKORY CLAY COMPANY P.O. Box 66 Hickory, KY 42051-0066 (270) 247-3042 Fax: (270) 247-1842 Email: [email protected] Website: www.oldhickoryclay.com SPINKS CLAY CO., LHOIST NORTH AMERICA P.O. Box 820 Paris, TN 38242 (731) 642-5414 Fax: (731) 642-5493 Website: www.spinksclay.com

UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] KAOLIN, CALCINED. Typically is a commercial product made from a specially prepared kaolin which is low in iron and alkalies. Microscopic and X-ray analyses show the calcined product to be principally mullite (3Al2O3-2SiO2) in association with an amorphous siliceous material. In fact, of the alumina present, 96% is converted to mullite. Iron content is not only low but in such a state of oxidation as to facilitate solid solution with the alumina. It is offered in particle sizes ranging from 3-mesh down to 2 mm. Typical chemical analysis of this brand of calcined kaolin (in %) is: 52-55 SiO2, 42-44 Al2O3, 0.75 Fe2O3, 1.70 TiO2, 0.10 CaO, 0.10 MgO, 0.20 K2O, 0.10 Na2O. The specific gravity is 2.67-2.72 and the softening point is slightly above cone 35 (1700°C) with initial deformation being detected between cone 34-35 (1750-1770°C). Outstanding properties of refractories containing this calcined kaolin are high refractoriness and retention of shape under load; high resistance to corrosion by slags, glasses, and glaze or enamel frits; resistance to thermal shock and high mechanical strength. It is being used in thermal shock bodies, refractories subjected to reducing atmospheres, kiln furniture compositions, thermal insulation bodies, low expansion bodies, permeable ceramic compositions, high temperature castables, investment molds for precision casting, as a placing medium, as a kiln wash, as gripping sand for high tension insulators, and in many other special refractory applications. KAOLIN, CALCINED SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com KAOLIN, FLORIDA. (Ball kaolin.) The kaolin deposits of Florida are found in the north central part of the state. They are secondary or sedimentary clays and occur mixed with white silica sand and pebbles. These deposits will average about 15-20% clay. Beneficiation is two-staged, degritting and dewatering. Degritting removes the pebbles, sand and heavies by washing, cyclonic separation and wet screening. A slurry of about 1.5-2.0% solid is sent to the dewatering process. This provides an averaging effect and also results in a clay of high purity and cleanliness. Dewatering is accom-

plished by gravity settling in the thickening vats to about 13-15% solids. This is pumped to vacuum rotary drum filters which discharge about 70% solids into mechanically extruded noodles onto a continuous belt feeding through a fourstage drying oven. Dry lumps can be pulverized using a Raymond mill and bagged. Both lump and pulverized clays are available for bulk overloading, but only ground clays are bagged. Chemical analysis (in %): 46.5 silica, 37.6 alumina, 0.36 titanium oxide, 0.51 iron oxide, 0.83 alkali oxides. Florida kaolin has unusual physical properties not ordinarily associated with most kaolins. It can be described as a ball kaolin because it combines the refractoriness and high white-fired color of kaolin with the strength, plasticity and particle size distribution of a ball clay. This type kaolin has a greasy property that, together with its very fine particle size, gives it a high degree of workability. It is very clean and uniform. Florida kaolin is used in jiggering and extrusion processes where a high degree of workability is required. Excellent flowing properties make it very useful in dry press operations. It is used in bodies where high strength is required. The bonding strength of Florida kaolin makes it useful in vitreous bonded grinding wheels, especially white wheels. Electrical porcelain and insulator manufacturers find the purity of Florida kaolin desirable. It has excellent suspending power and is widely used in glazes. The low titanium and iron content make it desirable in colored bodies and colored glazes where greater purity of color in pastel shades is desired. Small percentages in casting bodies are helpful, acting as a buffer for the electrolyte. KAOLIN, HYDROUS. Also known as “water-washed kaolin,” the term “hydrous kaolin” refers to the way in which the mineral is processed—i.e., water is used as a transporting and processing medium. In most cases, the kaolin is first mixed with water and chemical dispersants to create a milk-shakelike slurry. The slurried kaolin is then transported through pipelines to degritting facilities, where sand, mica and other impurities are extracted with the help of gravity. A centrifuge separates the fine kaolin particles from coarse particles, and the fine particles, still in the form of slurry, move on for further processing to enhance brightness. This is typically accomplished through bleaching, magnetic separation, flocculation, ozonation, flotation and/or oxidation, which will remove iron, titanium, organics and other undesirable materials. For manufacturers who want a delaminated clay product suited for lightweight coating applications, coarse particles are used. Delamination occurs as the coarse particles of kaolin—which when magnified appear as “booklets”— are broken into thin platelets. After delamination, the brightness of the coarse particles can be enhanced through one or more of the same processes used in the fine particle fraction. Large rotary vacuum filters then remove the water from the slurried kaolin, and large gas-fired spray dryers remove and evaporate the remaining moisture. The exact methods and equipment used to create hydrous or water-washed kaolin vary from supplier to supplier. Source: China Clay Producers Association, www.kaolin.com/ccpmin.htm.

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KAOLIN, HYDROUS SUPPLIERS

U.S. SILICA CO. P.O. Box 187 Berkeley Springs, WV 25411 (304) 258-2500; (800) 345-6170 Fax: (304) 258-8295 Email: [email protected] Website: www.u-s-silica.com KYANITE. (Cyanite.) 3Al2O3-3SiO2. This mineral has the same chemical composition as andalusite and sillimanite, but differs in crystal structure and physical properties. Kyanite ore has a specific gravity of 3.5-3.7 and a variable hardness, 4-5 parallel to the long direction of its blades and 6-7 across them. It is found in India, Africa, Sweden and the Appalachian region of the United States. Deposits in Dillwyn, Va., and Cullen, Va., have been worked for some years and are turning out many thousands of tons annually for use in refractories, ceramics and other associated fields. The American kyanite has an approximate analysis (in %) of: 54-60 alumina, 37-43 silica, 0.16-1.0 ferric oxide, 1.20 titanium oxide, 0.5 alkalies. The PCE runs 36-38. At about 2750°F, pure kyanite decomposes into mullite and silica with an accompanying decrease in specific gravity to about 2.9-3.2. The effect of this volume change on the finished product depends largely on the grain size of the kyanite and upon the physical properties of the bond used. The larger the grain, the greater the expansion. Kyanite from India is different in character from American kyanite in that its native occurrence is as surface boulders, while domestic kyanite is associated with quartz, from which it must be separated after grinding down to a workable mesh. In consequence, domestic Kyanite is not offered in grain sizes larger than 35 mesh, while Indian material can be calcined in lump form. Large grain sizes make an excellent grog. Although pure kyanite runs theoretically 63% Al2O3, good Indian kyanite will at times show about 62% due to the presence of free corundum in this ore. In general, Indian kyanite shows greater variation in consistency than domestically produced mineral. African kyanite, while resembling the Indian variety in that the ore is fairly pure in its native state, is far more inconsistent in quality, etc. American kyanite is offered raw and calcined to mullite, in grain sizes -35, -48, -100, -200 and 325 mesh. While the mullite form is quite stable as to volume change under heat, the raw form shows definite and substantial expansion, depending upon grain size and temperature. This property permits the use of raw kyanite as a balance against clay shrinkages in refractory bodies and it is, therefore, widely used in high-performance cements, ramming mixes, gunning mixes, monolithics, specialities and mortars. Domestic kyanite also goes into insulating brick, firebrick, kiln furniture and refractory shapes. While American kyanite’s first inroads into the clay products field took place in super-refractories (owing to its resistance to extreme temperatures), it is now making great headway in ceramic bodies not even subject to heat at all, after their original firing in course of manufacture. This is due to the well-known interlocking property of the crystal which gives much added mechanical strength to all ceramic compositions, even when fired at low heats during manufacture. The result has been a rapidly increasing use of kyanite in sanitary porcelains, wall tile, precision casting molds, brake disks, electrical porcelains and filters. CERAMIC INDUSTRY ³ January 2012

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ABRADORITE. A lime-soda feldspar. A typical composition (in %): 53 SiO2, 30 Al2O3, 13 CaO, 4 Na2O, trace H2O. (See FELDSPAR.)

LANTHANUM AND COMPOUNDS OF. (See specific compound listings, as well as RARE EARTHS.) LANTHANUM BORIDE. LaB4. A semiconductor used in TV tubes that emits an extremely bright beam of electrons when illuminated by light from a Nd:YAG laser.

Materials Handbook

LANTHANUM STRONTIUM MANGANITE (LSM) SUPPLIERS PRAXAIR SPECIALTY CERAMICS 16130 Wood-Red Rd., Ste. #7 Woodinville, WA 98072 (425) 487-1769 Fax: (425) 487-1859 Email: [email protected] Website: www.praxair.com/specialtyceramics LANTHANUM TITANATE. (Rare earth.) Re2O3-2TiO2. A light green powder reported to be of fine particle size. A major ingredient in many high dielectric constant ceramic capacitor compositions.

LANTHANUM BORIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com LANTHANUM CARBONATE. LaCO3. Used as a source of metal oxides in ceramic bodies. LANTHANUM OXIDE. La2O3. Mol. wt. 325.8; m.p. 2250°C. Soluble in acids and very slightly soluble in water. This oxide of a rare earth element occurs in monazite and bastnasite. It is marketed as the oxide or as other salts such as the oxalate, nitrate or hydrate. Purities available range up to 99.997%. It quickly absorbs water and carbon dioxide from the atmosphere. Its chief use is as an ingredient in nonsilica, rare element optical glass with oxides of tungsten, tantalum and thorium. Increases refractive index, decreases dispersion. It also is used in X-ray image intensifying screens which speed up X-ray exposure as much as 2-10 times so that diagnostic dosages may be reduced by as much as 80% with fewer retakes. Also used in barium titanate capacitors. LANTHANUM STRONTIUM MANGANITE (LSM). Lanthanum manganite is a p-type perovskite. By doping it with rare earth elements such as strontium, its electrical conductivity is enhanced. LSM powders are used as a cathode material in solid oxide fuel cells (SOFCs), and their mechanical properties (long-term stability, degradation, thermo-cycling behavior, etc.) must be compatible with the underlying electrolyte layer, which is typically YSZ. The LSM powders are usually applied to the electrolytes or other substrates by screen printing, and the final properties are strongly influenced by the firing temperature. The ability to custom-tailor physical properties is also important. Particle size distribution typically ranges from several micrometers to a sub-micron size, while a typical grain size distribution and surface area would be D90=2.9-3.1 μm, D50=1.8-2.0 μm, and D10=1.0-1.2 μm, with a BET value of 6.4 m2/g, respectively. A typical stoichiometry would be La0.71Sr0.22MnO3. Major impurities may differ, depending on the powder production process, and may include Al, Si and Fe. The LSM powder should posses a homogeneous microstructure and should be a single-phase product, i.e., without the existence of Mn3O4. (See also FUEL CELL MATERIALS and SOLID OXIDE FUEL CELL MATERIALS.)

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LANTHANUM TRIFLUORIDE. LaF3. Doped with neodymium oxide, the trivalent crystalline material is used for laser systems. LEAD BISILICATE. See LEAD SILICATE. LEAD BISILICATE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com LEAD CARBONATE. (White lead, basic lead carbonate.) 2PbCO3•Pb(OH)2. Mol. wt. 776; sp. gr. 6.7; decomposes at 400°C. Insoluble in water, slightly soluble in aqueous CO2 and soluble in acids. White powder prepared by treating lead oxide with acetic acid and carbon dioxide. Lead carbonate is an important constituent of glazes. It is preferred by whiteware, earthenware and vitreous tile manufacturers to other lead compounds. Small amounts are used in enamels and glasses. Lead carbonate has advantageous purity, particle size, water dispersive and suspensive qualities. Fine particles cause better suspension in raw glazes and quicker and more homogeneous fusions in frits. Due to high specific gravity of the oxides, difficulty in maintaining suspension may be caused. The release of CO2 and steam from lead carbonate under heat gives a degree of mechanical mixing and leaves the lead in a condition favorable to rapid chemical action which chemists describe as nascent. This is probably the cause for lead carbonate showing more rapid fusion. The presence of free lead and small amounts of iron are detrimental and have been stated to cause pinholing of the fired glaze in one case and discoloration in another. LEAD OXIDE. Two types of lead oxide are used in ceramics: litharge, or lead monoxide, and red lead. Litharge: PbO. Mol. wt. 223; sp. gr. 9.3-9.7; m.p. 888°C. Insoluble in water but soluble in alkalies, certain acids and some chloride solutions. Litharge may be made either in the yellow orthorhombic or red tetragonal form or in mixtures of each. Red lead: Pb3O4. Mol. wt. 686; sp. gr. 9.0-9.2; decomposes between 500-530°C. It is insoluble in water and is decomposed in some acids, leaving insoluble lead peroxide, PbO2. It is formed when litharge is roasted with air at temperatures somewhat below 545°C. The reaction is never complete in commercial practice and the product most widely used by the ceramic trade usually contains about 75% true red lead and 25% litharge. Red lead is sometimes preferred to litharge because the extra oxygen it carries, which it gives off at a low red heat, helps to assure an oxidizing condition in the melt and prevents reduction to metallic lead.

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Lead and its oxide and other compounds are derived from the mineral, galena, PbS, which is mined in Kansas, Missouri, Idaho, Utah, Oklahoma, Mexico, Australia, Canada, Germany and Peru. Lead oxide is used quite extensively in optical glass, electrical glass and tableware. It increases the density and refractive index of glass. In addition it can be cut more easily than other glasses and has superior brilliance, both of which make it good for cut glass. Taking into consideration color, density, brightness, durability, melting and working, a high grade cut glass ware can be made from 42% SiO2, 48% PbO, 3% Na2O and 7% K2O. Lead glasses may be formulated with a wide variety of electrical and acid resisting characteristics; desirable properties such as weather resistance, electrical resistivity, etc., will depend upon the total composition of the glass. Lead has many advantages as a glaze ingredient. The superiority of lead glazes lies in their brilliance, lustre and smoothness, which are due to their lower fusion point and viscosity. Lead glazes are, in general, highly resistant to water solubility and chipping, and have few faults in texture and bond. They have high mobility, refractivity and elasticity and are softer than leadless glazes. Lead glazes are said to be more foolproof in the plant, since errors in processing and composition affect the properties of the finished ware to a lesser degree. All investigators agree that the use of fritted glazes, in which all of the lead is fritted, has important health advantages. In this way the raw lead oxide is converted into relatively harmless lead silicates which are much less soluble in dilute acids or gastric juices. Lead silicates are more slowly absorbed after entering the respiratory system, and can be eliminated with less lead absorption. Of the lead silicates, the bisilicate (2PbO2SiO2) is much less soluble than the orthosilicate (2PbOSiO2) or the metasilicate (PbOSiO2). When dustless lead silicate is used in place of lead oxide, the lead hazard is practically nonexistent. Alumina has the greatest effect in reducing lead solubility, and silica and lime help to some extent while magnesia has very little effect. Not more than 0.45 equivalent of lead is permissible in a chrome-tin pink. High lead in a glaze containing uranium tends to a deep orange color, while those free from or very low in lead are of a lemon hue. A dark orange-yellow is obtained with this glaze, when fired at cone 1: PbO 1.0, Al2O3 0.3

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SiO2 0.20 U2O3 0.02

Lead oxide also is used in enamels. With an increase in lead and a corresponding decrease in potash, with flint constant, enamels become more fusible, have less tendency to craze and become more refractive, but are less durable in acid fumes. Litharge is extensively used in the production of dry process cast iron enamels, particularly acid-resisting enamels, and is practically indispensable in that field. The most successful of the porcelain enamels for aluminum contain relatively large amounts of lead oxide, usually in the range of 45%. These enamels have been found to give good weather resistance although fired at temperatures below 1000°F. Porcelain enamel frits for zinc-containing aluminum alloys have been prepared for application as low as 850°F. Lead is an important constituent in enamels for application to glass. These enamels are essentially modified lead borosilicates containing approximately 50% PbO. LEAD, RED. (See LEAD OXIDE.) LEAD SILICATE. (Lead bisilicate, lead monosilicate and tribasic lead silicate.) There are three types of fritted lead sili-

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2012 Edition

cates available for use in raw glazes, glass batches and enamels: 1. A 15% SiO2, 85% PbO composition, which is approximately the eutectic mixture of lead orthosilicate (2PbOSiO2) and lead metasilicate (PbOSiO2), melts at 725-775°C and is free from uncombined lead oxides and silicate. This material is commercially called lead monosilicate. The term lead monosilicate is not strictly accurate, since lead monosilicate would more properly refer to the lead metasilicate composition (PbOSiO2). It is used, however, to distinguish the basic lead silicate from lead bisilicate. 2. A composition of 65% PbO, 34% SiO2 and 1% Al2O3 is commonly called lead bisilicate. Either of these materials offers a number of practical economies in plant production and allows the introduction of lead, with its consequent benefits, in an easily handled, dustless and safer form. The mechanical and volatilization losses of lead are, thereby, reduced to the minimum. The monosilicate can be used competitively from a cost standpoint to replace lead carbonate, red lead or litharge. For specific advantages of lead compounds in ceramic bodies, see LEAD OXIDE. 3. A composition of 92% PbO, 8% SiO2, which corresponds to the eutectic mixture of 4PbOSiO2 and 2PbOSiO2, has been used by the glass industry in recent years. It is called tribasic lead silicate. A large amount of work has been done on the applications of lead-fluxed bodies of extremely high dielectric strength. The lead silicates and special lead frits have been used. A wide firing range for lead-fluxed steatite has found commercial application.

LEAD SILICATE

LEAD ZIRCONATE TITANATE SUPPLIERS APC INTERNATIONAL LTD., AMERICAN PIEZO CERAMICS P.O. Box 180, Duck Run Mackeyville, PA 17750 (570) 726-6961 Fax: (570) 726-7466 Email: [email protected] Website: www.americanpiezo.com LIGNOSULFONATES (LIGNIN). Derivatives of the bisulfite pulping process, lignosulfonates are anionic, surface active polyelectrolytes. The lignin polymer with branched polyaromatic chains can be modified to vary by cation, degree of sulfonation and purity, and average molecular size. Lignin processing technology has developed aqueous-based dispersants and binders for various ceramic applications, including structural clays, whitewares, technical ceramics, refractories and related areas of cement, concrete and gypsum board. As effective clay modifiers, lignin dispersants can improve tile and casting slip rheology, reduce free water for brick extrusion, and provide lubricity and plasticity for both extruded and dry-press ceramics. As a binder, lignin may increase both green and dry strengths of ceramic pieces with less than optimum body compositions. Lignin addition rates of 0.10-0.15% for fine grain and 0.20-2.0% for coarse ceramic materials will improve handling in prefiring stages of ceramic manufacturing. (See BINDERS.) LIGNOSULFONATE SUPPLIERS

LEAD ZIRCONATE TITANATE. Pb(Zr0.4Ti0.3)O3 to Pb(Zr0.9Ti0.1)O3. Also known as PZT ceramics. Used mainly in the manufacture of piezoelectric ceramic elements. The wide range of possible compositions provides a wide range of dielectric constant values, piezoelectric activity and primary transition temperatures. These are normally greater than possible with barium titanate. Small additions of niobium, strontium, barium and antimony serve as modifiers. Two techniques for producing PZT powders are used today. Calcining (CMO) is the more common method of powder production, and the calcine is then formed and fired in its final shape. A more recent development is the molten salt synthesis (MSS) method of synthesizing PZT powder. X-ray diffraction has shown powders produced this way to have a mean particle size of 0.2 μm. Mean particle size ranges for CMO powders were reported to be 3.27-6.08 +m at 3 min of calcining, and 0.52-1.24 +m after 20 min of calcining. One very useful composition contains 45 mol% PbZr02. The Curie point of this body is 340°C. PZT is the most widely used polycrystalline piezoelectric material. Its electrical output can measure pressure. It is used in hydrophones, which permit listening to sound transmitted through water. One variation of the PZT ceramics is PLZT ceramics (leadlanthanum zirconate titanate). They are a range of ferroelectric, optically active, transparent ceramics based on the PbZrO2TiO2 system. When hot pressed, they can reach 99.8% theoretical density. For device applications of PLZT ceramics, the ratio which is important is x:65:35, where x is lanthanum (8-10%) and 65:35 is the PbZrO3:PbTiO3 ratio. They have basically the same characteristics as PZT ceramics and are frequently finding use as filters, oscillators and vibrators in many areas. Also used for optical shutters.

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LIGNOTECH USA INC. 100 Grand Ave. Rothschild, WI 54474 (715) 355-3603; (908) 612-0948 Fax: (715) 355-3648 Email: [email protected] Website: www.lignotech.com LIME. (Calcium oxide.) CaO. Mol. wt. 56; sp. gr. 3.4; m.p. 2572°C; boils at 2850°C and is soluble. It is introduced into ceramic mixtures in several different forms. In pottery bodies and glazes, it is bought as whiting (calcium carbonate) or dolomite (calcium carbonate and magnesium carbonate). In glass batches, it is introduced by limestone, burned lime (calcined limestone) and dolomite. In the enameling industry, it is used in the form of whiting. (See DOLOMITE.) Lime as CaO is not found in nature. Calcium carbonate, which is the chief source of lime, is found in the form of the minerals calcite and aragonite. Impure calcite occurs as the rock limestone in large quantities in many parts of the world. Limestone may vary from pure calcium carbonate to pure dolomite, CaMg(CO3)2. Commercial lime may contain as much as 45% magnesia and such impurities as silica, iron oxide and alumina. Commercial limes are classified according to their relative content of CaO and MgO: high-calcium lime (<5% magnesia); magnesian lime (5-25% magnesia); and dolomitic lime (25-45% magnesia). A rich lime is one containing <5% total of silica, alumina, iron, etc. Use of the term lime in ceramics generally implies some form of calcium carbonate, whiting, chalk or ground limestone sold as whiting. The term is much broader, however, when used with reference to glass, as it may mean either a high calcium limestone or a dolomitic limestone or the oxide as burned lime made from either of these types of stone. Occasionally the hydrated form of lime is used. The chemical requirements of lime used in glass vary with the type of ware produced. The combined CaO and MgO should be at least 89% for bottle glass, 91% for sheet glass,

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LIME

93% for blown glass, 96% for rolled glass and 99% for optical glass. The iron oxide should be practically zero for optical glass, whereas in bottle glass as much as 0.5% is permissible, with nearly the same limits for blown or sheet glass. The silica or alumina may run as high as 15% for bottle glass, but should be very much less for other grades. Sulfur and phosphorus must be low in the anhydride forms, not exceeding 1% for bottle glass and as low as about 0.2% for optical glass. The quantity of carbon dioxide present should not be more than 3% with quicklime and 5% with hydrated lime. Quicklime generally is used in the pulverized form, and while specific sizes vary among different plants, the general limit is that it shall pass a 12-mesh sieve. Limestone occurs in many parts of the world, some of the purest being found near St. Louis and in Kentucky. As whiting, lime is found in England as a defined chalk, such as the chalk pits of Dover. As dolomite, it is found in various parts of the world. In the United States, the best known deposits are in northern Ohio. Wollastonite is a form of calcium silicate and at times it is said to constitute the chief mineral of the rock mass. This type of limestone is found in California, in the Black Forest of Germany and in France. In glass, lime is one of the most important of the common batch ingredients. Usually the dolomitic limes or magnesium-calcium limes are used not only because of the beneficial effects of the magnesium in the glass batch but also because of the more readily fluxing action imparted to the glass batch by the dolomitic lime. This lime is used in the form of crushed stone of various sizes, groundburnt quicklime or oxide, and as lime hydrate. Dolomitic limes increase the modulus of rupture of window glass and it is altogether possible to use dolomitic lime containing as much as 43% MgCO2 or 43% MgO. Lime gives to glass, when added in proper quantities, stability or permanency, hardness, viscosity and tenacity, and facilitates melting and refining. Lime decreases the viscosity at high temperatures but increases the rate of setting in working range. It greatly reduces the crushing strength when present in quantities >12.9%. When existing in proper proportions with the soda to make six silica equivalents to each one of lime and soda and properly melted, it gives the highest tensile strength. To increase the lime so that the glass will contain more than 12.83% calcium oxide, will tend to make the glass hard, brittle and more difficult to fuse into a perfect glass. Tenacity and hardness increase up to ~13.2% calcium oxide, after which there is quite a rapid decrease in these properties. The use of dolomitic limestone is said to prevent what is known as soda bloom, this elimination being due to the magnesium in the batch. It also adds luster to the ware. The manufacture of soda ash glasses may be made successful with a limited proportion of lime. The proportion of soda to lime is close to 2:1. In glasses which contain more than 8% lime, sulfate of soda should be present to some degree. It was found that all lime glasses devitrify with a greater velocity than glasses in which the lime was replaced in part by magnesium. Tests show that devitrification occurred in glasses containing low calcium. In general, it may be said that soda contents of amber and emerald green glasses are usually greater than those of flint and light green glasses, and that the maximum lime content which can be used in dark green glasses, such as emerald green, is less than that which can be used in flint or amber. Magnesium lime or dolomitic lime is largely used because of its low iron content. Dolomitic lime seems to have a more powerful fluxing action and a glass using dolomitic lime is said to fine or plain up quicker than one using lime from another source. A dolomitic limestone also will tend to reduce the amount of devitrification range in the glass. As whiting or as fluorspar in amounts not exceeding 3%, lime, when added to an earthenware body, increased the CERAMIC INDUSTRY ³ January 2012

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shrinkage very markedly and decreased the porosity, somewhat heightened the translucency, and very decidedly raised the strength. Whiting is more effective than fluorspar in equal amounts in decreasing shrinkage and increasing porosity. Fluorspar, on the other hand, surpasses whiting in promoting translucency and raising the strength. Whiting or fluorspar in amounts not exceeding 3% do not produce swelling. Slips used in the sanitaryware industry, especially that part which makes its product of a fireclay mixture, contain a certain percentage of calcium carbonate. Shaw found that unless >1% lime was present, a clay content of >40% requires a feldspar content of >15% to get sufficient vitrification at cone 9; 10% lime can be added to a slip which contains >40% clay. More than 10% lime is likely to produce a slip which will attack the glaze too vigorously and destroy opacity. Satisfactory slip is said to occur anywhere within the following limits (in %): 20-45 feldspar, 10-40 flint, 30-60 china clay, 10 max calcium carbonate. The lime used in pottery as calcium carbonate is usually in the form of whiting and is found in England in the immense chalk cliffs of Dover and surrounding country. It is used in very small amounts for fluxing and imparting white color to the body. Composition: 96% min calcium carbonate, 1.5% max silica. Calcium carbonate is not used to the same extent in enamels as it is in glasses and glazes. This is probably due to the fact that the average burning range of enamels is lower than that of either glasses or glazes, and calcium carbonate exerts strong fluxing action only at high temperatures. It is used to a certain extent in refractory enamels, and when so used it probably has about the same fluxing action as an equivalent weight of barium carbonate or zinc oxide. In less refractory enamels, calcium is generally introduced in the form of fluorspar in which form it acts as a strong flux and an accessory opacifier. In a leadless type of matte glaze, calcium in combination with chrome stain produces a fine green. Calcium and zinc produce a pinkish to brownish shade, while calcium and barium produce a dark green. Calcium and magnesium produce a brownish shade, and calcium and lead produce a fine bright green. In the regular type of Bristol glaze with a low feldspar content (i.e., lower than 0.4 equivalent), maximum glass is obtained when the CaO:ZnO ratio is less than 1:1, while with higher feldspar the ratio must be higher, at least 3:1. The most feasible mixture of lime in combination with feldspar, clay and silica is as follows: 0.60 K2O, 0.40 CaO, 0.639 Al2O3, 4.829 SiO2. This mix starts to deform at standard cone 3 and is completely deformed when cone 3 is about 75% deformed. In a white Bristol glaze, lime acts as a flux in most cases, but there are cases when it acts as an accelerator. Lime obtained from calcium phosphate seems to have a greater effect on the opacity of a glaze, tending to greater opacity. In a soda lime glaze used for salt glazing, alumina may replace the lime in part or even completely without serious results. The addition of lime in a salt glaze makes a better glaze. The eutectic of a mixture of whiting in orthoclase feldspar is very close to 3% whiting, 97% feldspar. LITHIA. Li2O. The oxide of lithium, usually added to ceramic batches by means of chemically prepared lithium compounds, or by means of one of the natural oreslepidolite, petalite, amblygonite or spodumene. Lithia is a very powerful flux, especially when used in conjunction with potash and soda feldspars. It is a valuable component in glasses having a low thermal expansion where its use permits the total alkali content to be kept to a minimum. The low thermal expansion properties also are exploited in flameproof ceramic bodies and glass ceramics where the formation of beta spodumene is the basis for oven-to-tableware

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production. It also enables the production of certain glasses having high electrical resistance and desirable working properties. A relatively high content of lithia allows the production of glasses that transmit ultraviolet light. Glasses containing lithia are much more fluid in the molten state than those containing proportionate amounts of sodium or potassium, and the successful use of lithia in glassmaking lies in the fact that much smaller amounts are required to produce a glass of the necessary fluidity for working without sacrificing the desired physical and chemical properties. In addition, lithia is being utilized to increase furnace capacity, decrease melting temperatures and increase production capacities. For further details on the action of lithia in glass, see SPODUMENE. Lithia has been widely used in the production of pottery glazes of high quality. The addition of 1% lithium carbonate in the frit or the fluoride or silicate in the mill to dinnerware, electrical porcelain and sanitaryware glazes has been found to increase the resulting gloss to a marked degree. In electrical porcelain it also is of value in producing a glaze of high strength and resistance to weathering. Due to its strong fluxing properties, the use of 9-12% lithium carbonate permits the use of greater amounts of alumina, calcia and silica in raw alkaline glazes, thus giving a more stable glaze. Such glazes may still be sufficiently alkaline to produce the beautiful and vivid copper blues and other typical alkaline glaze colors. In chinaware glazes, the addition of 0.5% lithia usually gives a decided improvement of fluidity of the glaze, producing greater uniformity and giving an increased gloss. When used in place of lead oxide in a glaze, there is less tendency to vaporize and coat the kiln and kiln furniture with an undesirable glaze. This effect is especially noticeable above cone 2, and has been used to prevent the glazing of the inside of small tunnel kilns in electrical porcelain production. Lithia is an effective mineralizer in ceramic bodies. In refractory specialties, structural clay products and the like, lithia as petalite is effective in reducing thermal expansion and improving thermal shock properties. For use of lithia in glazes, see LITHIUM CARBONATE, SPODUMENE and other lithium compounds. In porcelain enamels, lithia acts as a strong flux, serving to reduce firing temperature and time. Because of its low molecular weight, small percentages have a marked effect. Depending upon the compound employed, it can be used either in the smelter or in the mill. The excellent fluxing properties of lithia serve to improve the working qualities of abrasion-resistant enamels for dry-process cast iron. From 2-2.5% Li2O have been used. In dry-process enamels, the lithia must be added to the frit batch and not as a mill addition. For use of lithia in whiteware bodies, see SPODUMENE. LIMESTONE. Limestone is a sedimentary rock composed of the minerals calcite and aragonite. It is used as building material, as white pigment or filler in products such as paints, and as a chemical feedstock. LIMESTONE SUPPLIERS UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] LITHIUM. Li. The lightest metal known. Many of the lithium salts, particularly the carbonate, tend to resemble salts of the alkaline earth metals in chemical behavior, rather than the salts of the alkalies. (See also specific compound listings.)

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LITHIUM ALUMINATE. LiAlO2. Used for depositing III-V compounds for blue lasers and LEDs, as well as superconductor thin films. Also used to seal the reactant manifolds and corners of molten carbonate fuel cell stacks. LITHIUM ALUMINATE SUPPLIERS PRAXAIR SPECIALTY CERAMICS 16130 Wood-Red Rd., Ste. #7 Woodinville, WA 98072 (425) 487-1769 Fax: (425) 487-1859 Email: [email protected] Website: www.praxair.com/specialtyceramics LITHIUM CARBONATE. Li2CO3. Mol. wt. 73.89; density 2.094 g/cm3 (20°C); m.p. 720°C; specific heat 0.315 cal/g/°C. White powder, slightly soluble in water (about 1 wt%), has a higher vapor pressure than the other alkaline carbonate. In enamels where it is desired to introduce free lithia in the smelter batch as a flux, lithium carbonate is extremely effective, since it decomposes at 723-1270°C. When added to the smelter batch, the resulting enamel has a lower melting point, hence greater fluidity, a smoother surface and increased gloss. Such inherent characteristics as acid resistance and surface hardness are not impaired. White lithium carbonate is relatively insoluble in water. It was recently used in glass for TV tubes. It is constantly fed to aluminum refinery baths (i.e. high temperature) where its benefits include a lowering of bath temperature and an energy savings in electrolysis. It also scavenges fluoride ions, minimizing an effluent problem. In dinnerware glazes it is of value as a frit component of leadless glazes. (See LITHIA.) LITHIUM CARBONATE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com SQM NORTH AMERICA CORP., INDUSTRIAL 2727 Paces Ferry Rd. S.E. Ste. 2-1425 Atlanta, GA 30339-6160 (770) 916-9426 Fax: (770) 916-9401 Email: [email protected] Website: www.sqm.com LITHIUM FLUORIDE. LiF. Used as a flux and minor opacifier in porcelaim enamels and glazes, or as crystals in infrared instruments. LITHIUM FLUORIDE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com

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2012 Edition

LITHIUM SILICATE. Lithium silicate-based glass-ceramics have been developed for hermetic sealing to high-strength superalloys. Because of their high strength and toughness, these glass-ceramic sealed components are able to withstand very high internal gas pressures. LITHIUM TITANATE. LiTiO3. Used in batteries, lithium titanate enables faster recharging than lithium-ion batteries. Applications also exist in fuel cells and solar energy. LITHIUM ZIRCONATE. Li2ZrO3. As a carbon dioxide (CO2) absorbing material, lithium zirconate is a good candidate for use in CO2 reduction technologies at high temperatures (700-1100°C). LOW-TEMPERATURE COFIRED CERAMIC POWDERS. Powders designed for use in low-temperature cofired ceramic (LTCC) applications. (See also DIELECTRIC POWDERS.) LSM. (See LANTHANUM STRONTIUM MANGANITE.) LUBRICANTS. Substances which facilitate the flow of nonplastic, or poorly plastic, materials in the formation of dense compacts under pressure. Lubricants, which may be liquids or solids, either organic or inorganic, are particularly useful in dry pressing. Pieces formed under high pressure are apt to stick to the die, and even more so if the die is of intricate design. It has been shown that proper lubrication of the die and of the powders to be pressed does much to equalize pressure in the piece. Lubricants reduce the friction between particles, and particles and die surfaces. This results in denser compacts, possible use of lower forming pressures, and easier ejection. According to some investigators, the major cause of pressure variation is due to die surface friction. It has been shown by them that a stearic acid lubricant applied to the die walls completely eliminated pressure variations. Since it is impractical, in many cases, to lubricate the die after each operation, lubricants must be added to the powders. Lubricants can be added directly to the powder batch, or, in other cases, special techniques must be used, such as hot mixing to disperse low melting point solids. The total amount of lubricants, with other special additives, ranges from ~0.1-~10% of batch weight. The lubricants themselves usually are used in less than 5% amounts. Actual concentrations depend on the basic nature of the body and the complexity of the shape. Some lubricants also serve as binders and plasticizers. These are beneficial secondary functions and might serve as a basis for selecting one lubricant over another. Other factors to be considered are the compatibility of the lubricant with the body and the manufacturing processes, possible discoloration in the fired state, undesirable residues and the effect on glaze application Descriptions of typical lubricants which have been used in the ceramic industry follow: Alginates. Colloidal carbohydrate compounds, water soluble, which thicken ceramic bodies and facilitate pressing and extrusion operations. Camphor. A whitish, water insoluble material with a m.p. of 174-197°C. Soluble in several organic liquids. Cetyl Alcohol. A water-insoluble, white crystalline powder having a m.p. of 49.3°C. Has lubricating value due to its fatty nature. Graphite, Talc, Clay and Mica. Useful lubricants, particularly when finely pulverized, because of their platy nature. The plates tend to slide over one another and also deter sharp, hard particles from being embedded in the die surfaces.

LITHIUM SILICATE

Kerosene-Lard Oil. These mixtures, sometimes known as die oil, can be added directly to dry powders, or else applied to die surfaces. It is the lard oil which provides the lubricating properties. This is a relatively inexpensive lubricant, but it probably should not be used where a glaze is to be sprayed on the unfired piece. Lignosulfonates. An organic material derived from wood pulping which can provide improved plasticity and reduced forming friction. Some lignosulfonate products contain additives to further enhance lubrication. Also function as binders. (See BINDERS.) Methyl Cellulose. Synthetic gum increases the viscosity of water phases; gives a body increased workability. Mineral Oils. Petroleum products which have viscosities similar to other oily liquids. No. 4 Fuel Oil. A petroleum product of moderate viscosity, that might be used as are kerosene-lard oil mixtures. Polyvinyl Acetate. Available in powder or emulsion form. Can be made to be stable with water. Polyvinyl Alcohol. Colorless plastic available in several degrees of hydrolysis. These variants lend different properties in ceramic usage. Starches. Specially prepared for the ceramic industry; reportedly serve as lubricants due to a retained superficial water film. Stearates, Dispersed. Water-dispersed metallic soaps act as lubricants. Dispersion eliminates dusting and permits dilution to proper concentration. Are stable under proper storage conditions. Available with these ions: aluminum, ammonium, calcium, magnesium and zinc. Stearic Acid and Stearates. These are organic materials which give internal lubrication to powder mixtures and which are quite effective as die wall coatings. Wax Emulsions. Available in a number of concentrations and types. They not only lubricate, but also lend strength and some plasticity. When used in milled bodies, these emulsions should be added late in the cycle to obviate any breakdown. Waxes, Solid. Relatively high melting point solid waxes are added by melting into the powder and then fully incorporated by further mixing. Waxes are generally selected for their physical, rather than chemical, attributes in the ceramic industry. LUBRICANT SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] LIGNOTECH USA INC. 100 Grand Ave. Rothschild, WI 54474 (715) 355-3603; (908) 612-0948 Fax: (715) 355-3648 Email: [email protected] Website: www.lignotech.com ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com LUTETIUM OXIDE. Lu2O3. White powder with mol. wt. 397.98, and cubic crystal structure. The material is insoluble in water but soluble in all common acids. It has two stable isotopes at 97.4% and 2.6%, and the major impurity is ytterbium oxide. It is the last member of the rare earth series, and is available in purities up to 99.9%.

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MAGNESIUM CARBONATE

LUTETIUM OXIDE SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com

M

AGNESIA CHROME. (See MAGNESIUM CHROMITE.)

MAGNESIA CHROME SUPPLIERS

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com MAGNESITE. (See MAGNESIUM CARBONATE.) MAGNESITE SUPPLIERS ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com MAGNESITE, DEAD BURNED. MgCO3. Magnesite which has been heat-treated to temperatures above 1450°C to produce a stable material suitable for use as an ingredient in refractory products. (See MAGNESIUM CARBONATE.) MAGNESIUM ALUMINUM SILICATE. (See BINDERS.) MAGNESIUM CARBONATE. (Magnesite, magnesia alba.) MgCO3. The mineral magnesite has a sp. gr. of 2.9-3.1 and a hardness of 3.5-4.5 Mohs. Chemically pure magnesium carbonate has a mol. wt. of 84.3 and sp. gr. of 3.0. It loses its carbon dioxide at 900°C, is slightly soluble in water and soluble in acids. Magnesite is quarried in China, Brazil, Korea, Australia, Russia, Austria, Manchuria, Greece and Czechoslovakia. Magnesium carbonate is also produced from sea water in California, Ireland and Japan, and from brines in Michigan and Mexico. In the refined or calcined state, magnesite is used in pottery bodies, glazes, and glass. (See DOLOMITES.) Light magnesium carbonate (basic magnesium carbonate or hydromagnesite), 3MgCO3-Mg(OH)2-3H2O, has a mol. wt. of 365, sp. gr. of 2.2 and is soluble, especially in dilute acids. It is made by boiling together solutions of magnesium sulfate and sodium carbonate. Light magnesium carbonate is used as an electrolyte in both ground and cover coat enamels. Added in amounts ranging from 0.1250.250%, it acts as a flocculant on the clay, improving and stabilizing the set and suspension characteristics. Magnesium oxide is the major constituent of a group of refractory products—basic refractories—that are used in cement kilns and furnaces for the metal-producing indusCERAMIC INDUSTRY ³ January 2012

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MAGNESIUM CARBONATE

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MAGNESIUM PHOSPHATE, MONO BASIC

tries. When used for this purpose, the magnesium carbonate is “dead burned” in rotary kilns to produce a hard dense pebble of varying size. This intermediate form is crushed and the particles graded to provide a mixture of particles according to a specific standard. The magnesium oxide is then mixed with other ingredients, including organic binders, in batch mixers and brick are formed by the dry press method. Such brick are available as chemically bonded brick or as fired ware. The chemically bonded brick are ceramically bonded in service. An interesting phase of their production is the use of metal covers for a significant amount of them. Metal-clad brick are reserved for areas of intense conditions. While more expensive than either clay or silica refractories, the added life and higher operating temperatures attainable with basic refractories seem to indicate the continued expansion of use of this material. An important number of chrome magnesite brick are being manufactured in which the magnesite is used with varying proportions of chrome ore. Magnesite also is used as a raw material to produce fused MgO. Fused MgO is used in refractory applications as an additive to improve high-temperature corrosion resistance to molten metal slag. Fused MgO also is used as an electrical insulating powder in the manufacture of sheathed heating elements. In glazes, magnesium carbonate acts as a refractory up to a relatively high temperature when it then becomes an active flux. The formation of magnesium silicate in glazes develops an elastic glaze and at the same time develops glazes of rather low expansion coefficient. Very often magnesium carbonate is used to check the fluidity of a glaze. This is a very desirable property when dealing with crystalline glazes. Magnesium carbonate also seems to improve adherence. In substituting an equivalent of magnesia for lime in a pink glaze similar to Seger’s, the mass was found to be more purple-red instead of a pinkish color. The purple-red will also be developed in Seger pink itself by the addition of magnesium carbonate. In a series of terra-cotta glazes it was found that magnesium also had an influence on the fusibility of this glaze. Those glazes having a 0.3 equivalent of magnesia had a greater covering power and were less absorbed by the bodies and other glazes. The presence of magnesia in glazes containing no zinc showed a slight increase in opacity. It was found that those glazes having more than 0.1 equivalent of magnesia and more than 0.2 zinc oxide crazed. An increase of the clay content decreased crazing in these cases. The glazes used in this work were burned to cone 6. In experiments run by Stull on inexpensive enamels for stoneware, he stated that magnesium possesses strong opacifying properties. In an enamel containing 0.25 equivalent of magnesium oxide, less tin oxide was required to produce the same degree of opacity as those containing no magnesium. It seems that the magnesium oxide was at least equally as good an opacifier in the Bristol type of glaze as the same molecular quantity of tin oxide. Magnesium carbonate plays a part in vitreous porcelain enamels but not as active as in other fields in the industry. It is used in some cases in mills where a particularly coarse enamel ground coat is to be made. It seems that the magnesium carbonate in the mill exerts an influence that helps to set the enamel properly. Often the addition of an exceedingly small percentage of magnesium carbonate in the mill batch will stop a run of fishscale. When used in an enamel mill addition, magnesium carbonate is used up to 0.25% as the average addition. It also is used quite extensively in ground coats as it has a very desirable effect on draining characteristics. It shortens draining time which is a factor in line production.

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Magnesium carbonate’s action in enamels is similar to that of calcium carbonate—it acts as a refractory until high temperatures are reached; then it acts as a flux, but not as violently as calcium. In enamels, magnesium carbonate will often stop crazing when added to the mix. As a smelter addition, magnesium carbonate acts as a secondary opacifier in some frits and also affects color. Magnesium carbonate is introduced into various glass batches to allow a lower annealing temperature, to increase the melting rate, to improve working properties and to diminish the tendency toward devitrification. (See DOLOMITE.) Most semiporcelain and vitreous ware manufacturers use a small amount of magnesium carbonate because of the white color it tends to impart. It was found that magnesium carbonate as a flux will enable vitrification to take place at a lower temperature. Comparatively, magnesium does not possess a wide vitrification range. In vitreous ware, magnesia tends to impart excellent color and strength, with moderate shrinkage. Very often an amount of 0.1 equivalent of this material in a body will tend to prevent it from blistering by prolonging the range of vitrification. In this type of body, 0.4 equivalent has a marked effect on the color of the ware and aids translucency. In an insulating body, as little as 5% added to a feldspathic porcelain mixture tends to shorten the vitrification range, causing the body to work poorly and break easily. Another disadvantage of magnesia in an insulator body is its tendency to make the porcelain stick under a vitrifying fire. In a porcelain body containing a number of active fluxes, magnesia has a very noticeable effect on the melting point and the temperature range of the body. In mantle ring bodies, calcined magnesite is used; the fire shrinkage is high and seems to increase with the amount of magnesium oxide in the batch. In this type of body with over 25% magnesium oxide, the burned strength will be less than bodies containing less than that amount. MAGNESIUM CHROMITE. MgO-Cr2O3. Spinel with m.p. of 1780°C. (See SPINEL.)

Materials Handbook

Thermocouple insulation comprises still another outlet for periclase. Since most of these go into nuclear applications, a high purity product is required. Both grain and preformed bushings are used to load the tubing. Densification is obtained by diameter reduction processes similar to those used in heating element manufacture. MgO is an important glaze constituent. (See MAGNESIUM CARBONATE.) Single crystals of MgO have received attention due to their use in ductile ceramic studies. Extreme purity is required in this area. Periclase windows are also of potential interest in infrared applications due to their transmission characteristics. MAGNESIUM OXIDE SUPPLIERS

UCM MAGNESIA INC. 510 Mulberry Ln. Cherokee, AL 35616 (205) 370-7102 Fax: (256) 370-7463 Email: [email protected] Website: www.ucm-magnesia.com MAGNESIUM PHOSPHATE. Mg2P2O8. Mol. wt. 223.68. Monoclinic crystals with density of 2.598 g/cm3 that are insoluble in water and soluble in acids. M.p. 1383°C. This material has been successfully used to replace tin oxide in raw, leadless sanitaryware glazes maturing at cone 8 or higher, resulting in satisfactory color, permanent opacity, brilliance and texture. It has worked well both in low-alkali and high-alkali glazes at this temperature range, but produces no opacity in glazes maturing in the range cone 2-6. Solubility in water: 0.02% MAGNESIUM PHOSPHATE SUPPLIERS

MAGNESIUM OXIDE. (Periclase.) MgO. Mol. wt. 40.32. Cubic crystals with density of 3.65 g/cm3; slightly soluble in water and soluble in acids. M.p. 2800°C. A synthetic mineral produced in electric arc furnaces or by sintering of amorphous powder. Specific gravity of pure crystal is 3.53 and Mohs hardness is 6-6.5. Made in varying degrees of purity, depending on raw material. Both natural and synthetic magnesites are used with higher purity fused products derived primarily from synthetic material. Refractory applications consume a large quantity of MgO. Both brick and shapes are fabricated at least partially of sintered grain for use primarily in the metal processing industries. Heating unit insulation is another major application for periclase. High purity levels have always been important in this industry, but types of impurities are of equal importance. For many years the industry standard was a product made from Indian magnesite (95%). Recently, however, a trend toward higher purity magnesite (99.5%) has been noted. Some seawater magnesite also is used. Principal advantages of periclase in this application are its thermal conductivity and electrical resistivity at elevated temperatures. Others include its cubic crystal structure, its crushability during compaction and its relatively low cost compared with other possible materials. Specialty crucibles and shapes also are fabricated from MgO. These are used in pyrometallurgical and other purifying processes for specialty metals. Both slip casting and pressing techniques are employed to manufacture shapes.

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BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com MAGNESIUM PHOSPHATE, MONO BASIC. (Mono magnesium phosphate.) MgH4(PO4)2-2H2O. Mol. Wt. 254.29. Hydroscopic white crystalline powder. Soluble in water and acids, insoluble in alcohol. Decomposes to orthophosphate at approximately 400°F. Mono magnesium phosphate can be used as a rapid setting cement, set by adding additional base such as dead burned MgO. A highly exothermic reaction results in di basic or tri basic magnesium phosphate, which are insoluble in water. This reaction proceeds quickly; however, it can be retarded by adding organic acids such as citric or by the addition of inorganic acids such as boric. The material is used as a bond in refractory gunning and cementing applications, and in solid mold dental investments.

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MAGNESIUM PHOSPHATE, MONO BASIC SUPPLIERS

REFRACTORY MINERALS CO. INC. 150 S. Jennersville Rd. West Grove, PA 19390 (610) 869-3031 Fax: (610) 869-9805 Email: [email protected] Website: www.phosphatebonds.com MAGNESIUM SILICATE. 3MgSiO3·5H2O. Used as a component in glass, refractories and other ceramic bodies. MAGNESIUM STEARATE. Also known as octadecanoic acid and magnesium salt, magnesium stearate is a white powder substance that is solid at room temperature. Magnesium stearate has a melting point of 88°C and is not soluble in water. Source: Wikipedia, http://en.wikipedia.org/wiki/Magnesium_stearate

MAGNESIUM ZIRCONATE. MgO-ZrO2. Unlike the other alkaline earth zirconates, no compound of magnesium zirconate is formed. It is commonly used with other dielectric materials in the range of 3-5% to obtain dielectric bodies with special electrical properties. A body composed of 95 wt% barium titanate and 5 wt% magnesium zirconate has dielectric constants of ~2000 at 24°C, 2200 at 60°C and 2000 at 85°C. Beyond this, the dielectric constant drops quite rapidly, being about 1000 at 140°C. A component of temperature-compensating ceramic capacitors, its function is to shift the Curie peak of high dielectric constant capacitor compositions (depress K at Curie temperature). Magnesium zirconate also produces coatings with high temperature erosion resistance and good thermal shock resistance. Highly corrosion resistant to molten metals. Common uses include thermal barrier coatings in gas turbine engine combustors. Magnesium zirconate refractories are also used as setter bodies for firing electronic ceramics such as titanates and hard ferrites. MAGNETITE. Fe3O4 or FeFe2O4. An iron oxide spinel used as a colorant in the production of pale green, celadon green, pale blues and black glazes. Also has ferromagnetic properties and is used as a permanent magnet. MAGNETITE SUPPLIERS

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com MANGANESE DIOXIDE. MnO2. Mol. wt. 87; sp. gr. 5. It is converted into Mn2O3 at 535°C. Is insoluble in water and HNO3 and soluble in HCl. It occurs in nature as the blue-black mineral pyrolusite, which is mined in the former USSR, Gabon, Ghana, Morocco, South Africa, India, Brazil, Mexico, and in small quantities in several U.S. states, including Tennessee, Mosntana and New Mexico. In glass, manganese dioxide is used as a colorant and decolorizer, though the latter use has now been practically abandoned in favor of selenium.

MAGNESIUM PHOSPHATE, MONO BASIC

As a coloring oxide in lead potash glasses, manganese produces an amethyst color, while in soda glass a reddishviolet is produced. Manganese suitable for such purposes should contain at least 85% MnO2 and not more than 1% iron oxide. In potash-lime glasses containing manganese, the coloring properties of manganese are more far reaching than in other glass batches. A reported red-violet batch is: 1000 sand, 300 potash, 620 red lead, 26 manganese dioxide, 50 niter. A smoky flame or organic matter in glass tanks will reduce manganese dioxide to a manganese salt, and as such it will lose its coloring power. The so-called burning out of manganese, which produces a green glass, may be said to be akin to the changes in valency of the manganese radicals. In a batch containing 40 lb Mn/1000 lb sand, it was found that the manganese content could be cut down to 10 lb by adding an oxidizing agent such as niter. Manganese is sometimes used in combination with powder blue to form colors; for example, powder blue in glass containing 3-6% cobalt oxide. In a glass batch containing 200 lb sand, 80 lb soda ash and 23 lb burned lime, 32 oz manganese and 1 oz powder blue are said to give a dark red at 1325°C. In the manufacture of amber glasses, especially the dark red-browns, manganese is used as a coloring agent in conjunction with iron. This, however, is more the practice in Europe, and in this country is only used to a limited extent. In whiteware bodies, manganese oxide (added as dioxide) may act as a mineralizer when added to alumina in some high-temperature electrical porcelain mixes. When spinel is thus formed, a dark red-brown color is imparted to the porcelain. In the pottery industry manganese oxide is used to give red, brown, purple and black colors to bodies and glazes. One of its most important properties is that of stability. It is often used to make a purple- or plum-colored speckled effect in pottery bodies and glazes. Granulated manganese oxide is frequently used to achieve speckled effects in buff-burning brick. Air-floated, it is used as a gray background in brick. Manganese should never be fritted if it is possible not to do so. A finer and brighter purple color can be obtained by the use of this oxide without fritting. In crystal glass, it is said that the combination of copper and manganese hydroxide serves to give very beautiful crystalline formations. Manganese is used in ground-coat enamels in combination with cobalt. This combination seems to have a peculiar property of bonding with the iron base—1.5% manganese oxide in a ground-coat batch is said to be sufficient. Too much manganese in an enamel ground coat will make it very brittle and destroy the bonding power. Manganese dioxide is a strong oxidizing agent and its use in enamels is primarily due to this fact. When used in an enamel batch, it disintegrates during smelting into manganous oxide and oxygen; and the latter, besides helping to fuse the enamel, changes some of the ingredients to the highest possible oxide. Manganese oxide is especially desirable in ground coats which must bear an excessively hot treatment, such as in sign work, and it reduces the possibility of overburning. Manganese dioxide cannot be used in white enamels in more than minute quantities as it will color the cover coat an amethyst purple. Because of its coloring property, it is used in many colored enamels. In enamels, the use of manganese oxide with nickel and cobalt oxides will practically eliminate reboiling, according to Clayford and King.

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MICA

MANGANESE DIOXIDE SUPPLIERS

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com MANGANESE OXIDE. MnO. Mol. wt. 70.93; m.p. 1650°C. Cubic green crystals with density 5.18 g/cm3. Insoluble in water but soluble in acids. In ferromagnetic ferrites manganese oxide is used as one of the primary constituents of the zinc-manganese type, where it may be present at 10-30 wt%. Manganese also is one of the major constituents of computer memory core ferrites, and in other types it may be used in minor quantities to obtain property modifications. A variety of grades and types of manganese compounds are utilized, ranging from high-grade ores to highly purified synthetic chemicals. Some of the common forms of manganese materials are MnO 2, Mn 3O 4, MnCO 3 and the hydrated oxides. In general, material with a fine particle size and a high degree of chemical purity is desirable; some of the more commonly occurring chemical impurities being alkalis, alkaline earths, iron and silica. MANGANESE SILICIDE. MnSi. Mol. wt. 82.99; m.p. 1280°C. Tetrahedral crystals with density 5.90 g/cm3. Insoluble in water and very slightly soluble in acids. METAL POWDERS. Any of a variety of metals supplied in powder form, such as molybdenum, niobium, tantalum and tungsten. METAL POWDER SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com METHYL CELLULOSE. (See BINDERS.) MICA. Synthetic mica is available in various powdered forms in organically bonded paper sheets; in a threedimensional, hot-pressed, machinable synthetic mica ceramic; and in a flexible sheet form. Synthetic mica has unusually high thermal stability. For example, a synthetic fluorphlogopite can be safely used at temperatures up to 1800°F, whereas muscovite mica, the most common commercial variety, is limited to temperatures <1100°F. Of considerable interest to the refractories field is vermiculite, a form of mica that, on rapid heating, expands 16 times accordion-fashion to form a light and inert material suitable for use as a grog in refractories or as an aggregate for the production of lightweight casting refractory concretes. CERAMIC INDUSTRY ³ January 2012

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MICA

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MOLYBDENUM CARBIDES

MICA SUPPLIERS IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com MICROCLINE. (See FELDSPAR.)

Materials Handbook

reheated after their initial heat-forming. This is in contrast to thermoplastics, which soften when heated and harden and strengthen after cooling. Thermoplastics can be heated, shaped and cooled as often as necessary without causing a chemical change, while thermosetting plastics will burn when heated after the initial molding. In addition, thermoplastics tend to be easier to mold than thermosetting plastics, which also take a longer time to produce (due to the time it takes to cure the heated material). Source: ThomasNet, www.thomasnet.com

MICROPARTICLES. Microparticles, such as those composed of polymethylmethacrylate (PMMA), are mixed into the ceramic paste/mud prior to placement in the mold. The material is allowed to set/form and is removed and fired in a kiln. The PMMA microparticles volatilize, forming small spherical cells and allowing the ceramic material, on completion of the firing process, to become a rigid porous object that can be used as ceramic filters, etc. MICROPARTICLE SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com MICROPARTICLES, PMMA. Poly(methyl methacrylate), or PMMA, is the synthetic polymer of methyl methacrylate. A transparent thermoplastic, the material is often used as a light or shatter-resistant alternative to glass. PMMA can be used in place of polycarbonate (PC) when extreme strength is not necessary. In addition, PMMA does not contain bisphenol A subunits that can be found in polycarbonate. It is often preferred due to its moderate properties, easy handling and processing, and low cost, but behaves in a brittle manner when loaded, especially under an impact force, and is more prone to scratching compared to glass. Source: Wikipedia, http://en.wikipedia.org

MICROPARTICLES, THERMOSET SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com MICROSILICA. SiO2. M.p. 1550-1570C. Sp.gr. 2.2-2.3 g/ cm3. Bulk density 150-700 kg/m3. An amorphous silicon dioxide (silica), consisting of sub-micron spherical primary particles and agglomerates of these. The material is highly reactive in cementitious and ceramic bond systems. Microsilica is a key ingredient in advanced low, ultra-low and cement-free castables. It is highly reactive during sintering, and leads to improved ceramic bonding (mullite, forsterite, etc.), both in high alumina and magnesite based products. It is also employed in mortars, gunning mixes and other unshaped materials. (See SILICA FUME.) MICROSILICA SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

MICROPARTICLES, PMMA SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com MICROPARTICLES, POLYSTYRENE. Polystyrene (PS) is an inexpensive and hard plastic used in common everyday items, including computer housings, model cars and airplanes, and foam packaging and insulation. Polystyrene is a vinyl polymer. Structurally, it is a long hydrocarbon chain, with a phenyl group attached to every other carbon atom. Polystyrene is produced by free radical vinyl polymerization from the monomer styrene. Source: The University of Southern Mississippi Polymer Science Learning Center, http://pslc.ws/mactest/plastic.htm

MICROPARTICLES, POLYSTYRENE SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com MICROPARTICLES, THERMOSETS. Thermoset, or thermosetting, plastics are synthetic materials that strengthen during heating, but cannot be successfully remolded or

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MICROSPHERES, HOLLOW. Hollow microspheres are derived from the hollow fraction of fly-ash, and sometimes are also refered to as cenospheres. Typical compositions are 27-37 wt% aluninas and are 55-65 wt% silica. Cenospheres are a lightweight aggregate consisting of closed-cell, non-porous spheres. They have an average true density of between 0.6-0.8g/cc. an average bulk density of between 0.35-0.45g/cc and a very low surface area to volume ratio. With an average crush strength of 2000 psi, systems with good strength-to-weight ratios can be achieved. Appliations include insulating refractory brick, lightweight castable products, gunning mixes, and lightweight tumbling media. MICROSPHERES, HOLLOW SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com MOLOCHITE™. Molochite is a highly calcined aluminum silicate produced from a specially prepared kaolin low in iron and alkalies. Adequate and prolonged heat treatment has brought about a product showing the maximum development of crystalline mullite which induces mechanical stability and resistance to thermal shock.

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Mullite conversion, which means the amount of mullite formed, is ~96% of the maximum possible determined from chemical analysis. Purity, low iron and alkali content, high calcination temperature, wide range of available gradings, low thermal expansion, low fired shrinkage and proven uniformity lend this material to a wide field of diverse applications. MOLOCHITE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com MOLYBDATE. A molybdate is a compound containing an oxoanion with molybdenum in its highest oxidation state of 6. Formulations containing molybdate are used as corrosion inhibitors in industrial water treatment, such as for closed recirculating systems, as well as multiple additional applications. Source: Aquatic Life, www.aquaticlife.ca

MOLYBDATE SUPPLIERS H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com MOLYBDATE, CALCIUM. (See CALCIUM MOLYBDATE.) MOLYBDENUM AND COMPOUNDS OF. Mo. At. wt. 95.95; at. no. 42; m.p. 4478°F; sp. gr. 10.2; valence 3, 4 or 6. A silverywhite metal produced by reduction of molybdic oxide (MoO3). Commercially available in powdered form or as the consolidated metal produced by powder metallurgy or arc-casting methods. Available in a high state of purity. Used for metalto-glass seals, and for filaments, screens and grids in radio and other vacuum tubes. It is used as electric resistive elements in vacuum furnaces, and in other gas-shielded furnaces, for temperatures up to 3500°F. Metallic molybdenum oxidizes easily above red heat. Other uses include electrodes for electric glass-melting furnaces, piercing points, and machine parts exposed to high-temperature nonoxidizing atmospheres. Its most recent use is in electro-optical applications. See also specific compound listings for additional information. MOLYBDENUM AND COMPOUNDS OF SUPPLIERS H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com MOLYBDENUM CARBIDES. MoC, Mo 2C. Mo 2C melts at 2310°C; MoC, at 2690°C. Mo2C is dark metallic-gray; MoC is gray with a metallic luster. Mo2C is stable in nonoxidizing acids but is dissolved by nitric acid. When heated in air, Mo2C is readily oxidized. The monocarbide, MoC, is decomposed by HF, HNO3 and by boiling H2SO 4, but is scarcely attacked by HCl and resists attack by cold KOH and NaOH solutions. It is readily attacked by halogens and by oxygen. Density of Mo2C from X-ray data is 9.2 g/cm3; that of MoC is 8.4 g/cm3. The modulus of elasticity of Mo2C is 32.7 x 104 psi. Supplier listings indicate paid advertising.

2012 Edition

MOLYBDENUM CARBIDES

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MULLITE, ZIRCONIA (FUSED)

MOLYBDENUM DISILICIDE SUPPLIERS CONTINUED Specific electrical resistivity of Mo2C is 97.5 +ohm-cm at 20°C and 181 +ohm-cm at the melting point. The corresponding values for MoC are 49 and 70 +ohm-cm, respectively. MOLYBDENUM CARBIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com MOLYBDENUM DISILICIDE. MoSi2. Mol. wt. 152.0; m.p. >3700°F. The commercial product contains approximately 60% Mo, 31% Si, 8% Fe, with small amounts of C, S, V, P and Cu. Principal use is for alloying iron and steel, but has some ceramic uses as well. Its outstanding resistance to oxidation in air at temperatures up to 1700°C makes it potentially useful for high temperature applications. Molybdenum disilicide is commercially available in high purity powder in various sizes down to -325 mesh. Molybdenum disilicide has a hardness of HRA 80-87. Its m.p. is ~2000°C, but there is some decomposition at the melting point accompanied by appreciable silicon loss. The crystal structure is tetragonal, 011b type, with dimensions a = 3.20 and c = 7.86 angstroms. X-ray density is 6.24 g/cm3. Electrical resistivity at room temperature: 21-27 +ohm-cm, depending on method of fabrication. CTE is 8 x 10-6/°C. Molybdenum disilicide is fairly strong, but not at all resistant to impact loading. Fabrication methods have great influence over strength, with modulus of transverse rupture ranging from 40,000-60,000 psi. Compressive strength varies from 100,000-350,000 psi. Appreciable strength is retained at least up to 1200°C. The 100-hr stress-to-rupture value at 1000°C is 13,500 psi. Molybdenum disilicide can be formed by powder metallurgical techniques such as hot pressing, or cold pressing and sintering. It can also be cast, but this is complicated by decomposition at the melting point. Ingots are porous and have very large grain size. The powder also can be formed into parts by slip casting and sintering, but this technique, while well known in the ceramic industry, is a relatively new concept which has only lately been applied to metal powder fabrication. The excellent resistance to oxidation at high temperatures combined with fairly good elevated temperature strength makes MoSi2 promising for elevated temperature structural applications where impact resistance is not a major consideration. Possible are gas turbine nozzle blades and furnace heating elements. Also, a metal-ceramic combination of MoSi2 and Al2O3 has been considered for use as kiln furniture, saggers, sand blast nozzles, hot draw or hot press dies, and induction brazing fixtures. MOLYBDENUM DISILICIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

industries. The theoretical chemical analysis (wt%) of mullite and five typical mullite materials are as follows:

MOLYBDIC ACID. MoO3-H2O (sometimes written H2MoO4). Formed when molybdic oxide is in contact with water. Very unstable. Loses water upon heating. MOLYBDIC OXIDE. (Molybdenum trioxide, molybdic acid anhydride and, in mineral form, molybdite.) MoO3. Mol. wt. 144.0; sp. gr. 4.50; m.p. 1463°F. Vapor pressure: 760 mm Hg at 2111°F. Rhombic crystals, colorless to yellowish-white. Slightly soluble in cold water, quite soluble in hot water. Soluble in mineral acids, and in aqueous solutions of ammonia and the alkalis, where it forms soluble molybdates. Forms insoluble molybdates with alkaline earths and other basic oxides. In glasses, glazes and enamels, small amounts (0.1-0.2%) act as a wetting agent or surface tension reducer. In whiteware bodies, small amounts (0.1-0.2%) give increased strength and lower firing temperatures due to the increased wetting action of the glass phase. In porcelain enamels, large amounts produce opacity, due to the crystallization of molybdates of the alkaline earths, lead or zinc, when the quenched frit is heated. Amounts >1% smelted in frits act as adherence promotors in cast iron enamels, sheet steel enamels, jewelry enamels and high temperature ceramic coatings. White frits (in which are smelted molybdic oxide, with or without antimony oxide) have excellent adherence when applied directly to steel at ~1300°F. Lead-bearing enamels containing molybdic oxide are used for enameling aluminum at 900-1000°F, and also can be used on cast iron or sheet steel.

Mullite bodies show a uniform rate of thermal expansion and are resistant to spalling and deformation under load. Their strength is due to the interlocking of long, needle-like crystals. Some authorities have stated that to get long crystals there must be present impurities which will promote their growth, but a mullite body with short, interlocking crystals is more stable to load-deformation at high temperatures. Mullite porcelains are used in spark plugs and laboratory ware. MULLITE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

MOLYBDIC OXIDE SUPPLIERS H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com MULLITE. 3Al2O3-2SiO2. M.p. 1810°C; softens at 1650°C. Can be synthesized by calcining Alabama bauxite of correct Al2O3:SiO2 ratio or blending and calcining alumina and kaolin in proper ratio. Precompacting of feed materials is required. Currently being offered in both calcined and fused forms with this analysis (in %): 71.7-76.2 Al2O3, 23.0-23.6 SiO2, 0.11-3.0 TiO2, 0.13-1.17 Fe2O3, 0.04-0.06 CaO, 0.05-0.06 MgO, 0.05-0.44 alkalies. Sp. gr. 3.156 Mullite occurs in nearly all ceramic products containing alumina and silica but, with the exception of refractories, is seldom introduced as such except as calcined kyanite. Mullite is rare in nature, one locality being the Isle of Mull, Scotland, where argillaceous sediments have been fused by igneous intrusion. The compound was formerly thought to be synthetic sillimanite (a name that still persists in some quarters). Mullite is very refractory, breaking up into corundum and liquid silica at 1810°C. In the manufacture of refractory and porcelain bodies, the desirable mullite is formed from the chemically similar minerals andalusite, kyanite and dumortierite, which decompose into mullite and silica at cone 13, cone 12 and cone 6, respectively. To break up sillimanite in the same way, cone 20 is required. Sintered and electrofused synthetic mullites (including zirconium mullite) are used in kiln furniture and refractories for the glass and steel

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WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com MULLITE, ZIRCONIA (FUSED). M.p. 1750ºC. Sp. gr. 3.5-3.6. Fused, high purity zirconia mullite grain is produced by the electric furnace fusion of Bayer process alumina and zircon sand. During melting, the zircon and alumina react to yield a mixture of mullite and zirconia. Fused zirconia mullite is composed of large, needle-like mullite crystals, containing co-precipitated monoclinic zirconia. Average crystal width is 100 μm, with an average length of 10,000 μm. Traces of dendritic, monoclinic zirconia and about 5% glass is present in the interstices between the mullite crystals. Fused zirconia mullite is used in specialty product applications where a high resistance to environmental corrosion and a low coefficient of thermal expansion are desirable properties. Applications include ceramic pressure casting tubes, setters and saggers, and refractory shapes requiring resistance to molten slag and molten glass. MULLITE, ZIRCONIA (FUSED) SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

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NEPHELINE SYENITE

Materials Handbook

MULLITE, ZIRCONIA (FUSED) SUPPLIERS CONTINUED 2270°C, and can be used as both a main component and as a dopant.

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com

N

ANOMATERIALS. Nanomaterials, or nanocrystalline materials, are commonly defined as crystalline materials which have an average particle or grain size of less than 100 nanometers (0.1 micron). A deliberate distinction is made between nanocrystalline materials and crystalline materials which are submicron. Sub-micron materials have an average particle or grain size of less than 1 micron. The relative percentage of interfacial atoms to total atoms in a material increases dramatically with decreasing size below 100 nanometers. The resultant properties of nanocrystalline materials thus have a much greater dependence on the contributions of interfacial atoms than sub-micron materials. Interfacial atoms are those on the surface of a particle, or in the grain boundaries of a consolidated material. Some unconventional mechanical, chemical, electrical, optical, and magnetic properties which nanocrystalline materials exhibit are attributed to this greater dependence on the contributions of interfacial atoms. NANOMATERIAL SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com

NEODYMIUM CHLORIDE. NdCl3. Soluble in water, alcohol and acetone. NEODYMIUM OXIDE. Nd2O3. Mol. wt. 336.5; sp. gr. 7.2. Soluble in acids and very slightly soluble in water. An oxide of a rare earth element, it occurs in monazite and bastnasite. It is marketed as the oxide or as other salts, such as oxalate, carbonate or chloride salts. Technical grade products contain more or less amounts of praseodymium and some lanthanum and other rare earths. Neodymium materials are available in purities of 38-99.99%. Neodymium oxide is used in glass in concentrations of 3-6% to give a beautiful violet color, red-violet in artificial light and blue-violet in daylight. It also is used to suppress the transmission of yellow (sodium) light in technical glasses. On the other hand, in heat-resisting glasses high in boric oxide, neodymium oxide functions better than any other known decolorizer. Neodymium-doped glass finds applications in the manufacture of lasers. Neodymium oxide is used extensively in the multilayer capacitor field to produce NPO capacitors. In combination with barium titanate, it produces a capacitor with no change in coefficient of capacitance over -100-300°F temperature range. It also is perfect for high temperature glazes, having a m.p. of

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NEPHELINE. (Nephelite.) K2O-3Na2O-4Al2O3-9SiO2. A comparatively rare double alminosilicate of potassium and sodium, occurring as hexagonal crystals or in massive form. It is higher in alkali and alumina, and lower in silica than are feldspars. The feldspathoid nepheline crystallizes from the magma, instead of soda feldspar, as a result of insufficient silica to form feldspar. It may be colorless white, yellowish, dark green or brownish, and has a vitreous luster. Mohs’ hardness 5.5-6; sp. gr. 2.5-2.6. Deposits are located in Ontario, Maine, Massachusetts, New Hampshire, Arkansas, New Jersey, Texas, Colorado, Montana and South Dakota, and most of Europe. (See NEPHELINE SYENITE.) NEPHELINE SYENITE. A holocrystalline, granular, igneous rock made up of nepheline (K2O-3Na2O-4Al2O3-9SiO2), potash feldspar (microcline), soda feldspar (albite) and such minor accessory minerals as mica, hornblende and magnetite. It is found in Canada, India, Norway and the former USSR. It resembles granite in texture but contains no free quartz. An analysis (in %) of commercial ceramic nepheline syenite from Blue Mountain, Ontario, is: 60.2 SiO2, 23.6 Al2O3, 0.08 Fe2O3, 0.35 CaO, 0.02 MgO, 10.5 Na2O, 4.8 K2O, 0.42 LOI. Iron—~2% in the original rock—has been removed from this material. For this composition, nepheline syenite has a mol. wt. of 447; sp. gr. of 2.61 in the crystalline form and 2.28 in the glassy state; and Mohs’ hardness of ~6. It starts to sinter at cone 08 and has a PCE of about cone 7. There is a eutectic between soda feldspar and nepheline which is a factor in the wide sintering range of nepheline syenite. In sanitaryware bodies, the substitution of nepheline syenite for potash feldspar makes possible a much lower firing temperature. A longer firing range with decreased warpage is noted when firing the ware in commercial tunnel kilns. Research in the development of low fired vitreous ware has demonstrated the fact that a cone 4 sanitaryware body can be made which will provide a very large reduction in the cost of fuel and refractories, plus the added advantage of a fast firing cycle. In floor and wall tile bodies, the lower fusibility and increased fluxing action of nepheline syenite permit the formulation of bodies maturing at lower temperatures. Direct substitution of nepheline syenite for potash feldspar in wall tile bodies lowers the absorption and moisture expansion and increases the shrinkage and mechanical strength. Floor tile bodies show less variation in thermal expansion with differences in thermal treatment than the corresponding feldspar bodies. Thermal expansion of talc wall tile bodies is lowered by the direct substitution of nepheline syenite for feldspar, although bodies fluxed with nepheline syenite alone have a higher thermal expansion than those fluxed with potash feldspar only. In electrical porcelain, the same general results as noted earlier may be expected: substitution of nepheline syenite for potash feldspar increases the firing range, increases strength, decreases absorption and increases shrinkage at the lower firing temperature. In semivitreous bodies, nepheline syenite produces increased vitrification. There is a wide range which results in less warpage. In bodies fluxed with nepheline syenite, the thermal expansion is greater than in corresponding feldspar bodies. This tends to promote a state of compression in the glaze and reduce crazing tendencies. Low-temperature vitreous bodies maturing at cone 3-5 can be formulated from clays and nepheline syenite without recourse to an auxiliary flux. Such bodies have a wide firing range and good strength. These bodies are highly translu-

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cent when prepared by wet milling, and by combining low temperature with a fast firing cycle a large savings is made in fuel, refractories and ware lost from warpage; furthermore, a wider color range in both body and glaze is made possible. The higher the nepheline syenite content of the bodies, the higher the thermal expansion and the smaller the variation in expansion with differences in thermal history. The addition of 5-10% flint raises the thermal expansion of the bodies so that typical semivitreous dinnerware glazes are placed under adequate compression and can be used for one-fire ware. Also, special high compression glazes have been developed for this use. For two-fire ware, excellent glazes are available which have good service characteristics and which mature at cone 01. A typical low temperature body formula (in %) is: 54 nepheline syenite; 6 flint; 24 kaolin; 16 ball clay. Due to its high alumina content, nepheline syenite is a good material for introducing alumina into a glass batch. It contains considerable alkali, a desirable constituent of the batch, and melts at a relatively low temperature. These advantages, together with the fact that it is taken into the melt very readily, make it a desirable addition to tank glasses. Substitution of nepheline syenite for potash feldspar on a chemical analysis basis in a typical opal glass batch is said to permit melting at a lower temperature, thereby affording the possibility of fuel economy and longer life of refractories. The resultant glass will have the same thermal expansion as the comparable feldspar glass, but softens at about 50°C lower temperature. The iron-alumina ratio of this material makes it particularly useful in glasses where low iron oxide content is of primary importance. Proposed Batch, lb1 Sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000 Nepheline syenite . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Burned dolomite lime . . . . . . . . . . . . . . . . . . . . . . . . . 169 Barium sulfate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Fused borax (pyrobor)2 . . . . . . . . . . . . . . . . . . . . . . . . . 27 Soda ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339 Arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 lb Decolorizer . . . . . . . . . . . . . . . . . . . . . sufficient quantity Cullet . . . . . . . . . . . . . . . . . . . . . . . 35% of batch weight 1 Not considering weight of cullet, the foregoing batch will produce ~1548 lb of glass. 2 Fused borax or pyrobor preferred, but if ordinary borax, which contains waters of crystallization, is used, it will be necessary to use 54 lb instead of 27 lb. (This is a typical container batch which is rather high in aluminum oxide and lime, but it has been found that this glass has great durability and strength, and the rate of production is increased due to the higher aluminum oxide content.)

Calculated to Glass, % Silica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70.30 Iron and alumina . . . . . . . . . . . . . . . . . . . . . . . . . . 2.36 Calcium oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.32 Magnesium oxide . . . . . . . . . . . . . . . . . . . . . . . . . 4.54 Barium oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50 Sodium oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.26 Potassium oxide . . . . . . . . . . . . . . . . . . . . . . . . . . 0.48 Boric oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.20 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.96 Glass-grade nepheline syenite is now refined by means of magnetic separation, making possible a granular concentrate with a constant low iron oxide content. In porcelain enamels, the obvious advantage again is the decreased fusion temperature possible. However, when substituting directly for feldspar, increased viscosity due to increased alumina makes it necessary to fire at nearly Supplier listings indicate paid advertising.

2012 Edition

normal temperature to get proper maturity. It also is possible, through the use of nepheline syenite, to incorporate considerably more alumina in an enamel without increasing the hardness of the enamel. This is desirable because increasing alumina generally reduces the solubility of the enamel. NEPHELINE SYENITE SUPPLIERS

ARKANSAS AGGREGATES INC. 174 Cornerstone Ct. Ste. B Hot Springs, AR 71913 (501) 520-0551; (501) 520-1132 Fax: (501) 520-5206 Email: [email protected] Website: www.arkansasaggregates.com

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com MINERAL DEVELOPMENT LLC P.O. Box 15872 Little Rock, AR 72231 (501) 988-0700 Fax: (501) 988-4843 Email: [email protected] Website: www.mineraldevelopment.com

UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] NICKEL CARBONATE. NiCO3. Sometimes used as an ingredient in ceramic colors and glazes. NICKEL CARBONATE SUPPLIERS ARLINGTON INTERNATIONAL INC., CERAMIC RAW MATERIALS 333 W. Drake Rd., Ste. 220 Fort Collins, CO 80526 (855) 494-0244; (970) 494-0244 Fax: (970) 494-0206 Email: [email protected] NICKEL OXIDES. Two of the nickel oxides are useful as colorants in ceramics: (1) nickelous oxide or green nickel oxide, NiO, and (2) nickelic oxide, nickel sesquioxide or black nickel oxide, Ni2O3. NiO has a mol. wt. of 74.7; sp. gr. of 6.6-7.5, is insoluble in water and soluble in acids and ammonium hydroxide. At

NEPHELINE SYENITE

400°C it oxidizes to Ni2O3, and at 600°C it is reduced back to NiO. It occurs occasionally in nature as the mineral bunsenite, though the commercial product is prepared by heating nickel hydroxide or nickel nitrate. Ni2O3 has a mol. wt. of 165, sp. gr. of 4.8, is insoluble in water and soluble in acids and ammonium hydroxide. It is reduced to NiO at 600°C. It is prepared by gently heating nickel nitrate or nickel chlorate. Both of the nickel oxides are ultimately derived from the nickel arsenide and nickel sulfide ores of Sudbury, Ontario, though a small portion comes from the garnierite (hydrous nickel magnesium silicate) ores of New Caledonia. Black nickelic oxide imparts a color to glass which is dependent upon the character of the alkali present. Nickel produces a bluish-violet in potash glasses and a violet tending toward brown in soda glasses. Nickel rates as one of the more powerful colorants, since one part in 50,000 produces a recognizable tint. Nickel oxide is apparently unaffected by oxidizing or reducing conditions. The unpleasant tint nickel oxide produces in the presence of soda makes its use rare in America, according to Scholes. Nickel oxide is sometimes used to decolorize potash glass. Nickel oxide and nickel silicate have an advantage over manganese dioxide for decolorizing purposes in that they are not as sensitive in changing oxidizing and reducing environments. Although a fairly good decolorizer, nickel oxide does not give a perfect complementary color, especially with soda glasses. In some cases, it is added with selenium and in place of cobalt oxide, but with some disadvantage. The use of nickel oxide in porcelain enamel compositions is usually confined to the ground coat, in which it is used with cobalt or cobalt and manganese. The amount of nickel oxide used is generally about 0.5%, though up to 3% is permissible. When adding nickel oxide to a ground coat which has contained only cobalt oxide, about three parts of nickel are added for each part of cobalt replaced. The substitution of part of the cobalt of a ground coat in favor of nickel saves on cost of materials, retains adherence and is generally trustworthy, though the durability is somewhat decreased. For a ground coat of high quality, the following combination of the two oxides is suggested: 0.4% cobalt oxide and 0.75% nickel oxide. When properly burned, the color gradually changes from blue to black. Nickel oxide also is used in cover-coat enamels to give what is known as a daylight shade for reflector units. In cover coats, nickel oxide and cobalt oxide are said to be equal in toughness. Harrison and Hartshom give this composition for a typical dark blue enamel stain: 33.8% nickelic oxide and 66.2% chromic oxide. Nickelous oxide is used in glazes to produce blues, grays, browns and yellows. According to Fence, the following glaze (fired to cone 5) will give a blue color when in combination with 0.15 equivalent nickel oxide: K2O 0.25 CaO 0.14 BaO 0.21 ZnO 0.40

} }

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NIOBIUM PENTOXIDE

In a glaze of this type, nickel oxide gives a brown with 0.15 equivalent ZnO, a strong reddish-purple with 0.25 equivalent ZnO, and a dark blue with 0.35 equivalent ZnO. Nickel salts have long been used in the porcelain enameling industry as a flashing on the part after pickling and prior to application of the P/E slip. NICKEL OXIDE SUPPLIERS ARLINGTON INTERNATIONAL INC., CERAMIC RAW MATERIALS 333 W. Drake Rd., Ste. 220 Fort Collins, CO 80526 (855) 494-0244; (970) 494-0244 Fax: (970) 494-0206 Email: [email protected] NIOBIUM BORIDE. NbB. M.p. >2900°C; density 7.2 g/cm3; Mohs’ hardness 8; resistivity 32 +ohm-cm. Also available as NbB2. NIOBIUM OXALATE. Nb2O5 5C2O4 2NH4O4. A white, watersoluble compound containing ammonia and crystal water. It is stable in air; however, slight moisture pickup is likely. Compared to other soluble niobium sources, oxalate is easy to handle and store because no protecting atmosphere is necessary to prevent hydrolysis, and no HCl-evolution (as for NbCl5) has to be considered. It is typically used in the production of catalysts, ferrites and other electroceramics. In ferrites, a homogenous distribution and thin layers of the dopants are desired for a proper adjustment of the magnetic properties, and a soluble compound is required to achieve these goals. As a result, niobium oxalate is often preferred over niobium oxide in these applications. When used to coat barium titanate ceramics for multilayer ceramic capacitors (MLCCs), niobium oxalate can significantly reduce sintering temperatures compared to niobium oxide. Source: H.C. Starck GmbH, www.hcstarck.de.

NIOBIUM OXALATE SUPPLIERS H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com NIOBIUM OXIDE. Niobates of sodium, cadmium and other common elements have been found to possess ferroelectric properties, many of the combinations having Curie temperatures of 200-275°C. A rectifier can be made by oxidizing niobium metal in steam. NIOBIUM OXIDE SUPPLIERS

Al2O3 0.3 { 2SiO2 2.0

A purplish glaze will result from the following composition. It contains 0.15 equivalent of nickel oxide and is fired at cone 5: K2O 0.25 CaO 0.20 BaO 0.30 ZnO 0.25

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Al2O3 0.3 { 2SiO2 2.0

H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com NIOBIUM PENTOXIDE. Nb2O5. Mol. wt. 266.6; m.p. 1520°C; density 4.47 g/cm3; CTE 6 x 10-7/°C (25-400°C). White rhombohedral crystals insoluble in water, soluble in H2SO4, HF and alkalis. (See NIOBIUM OXIDE.)

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NIOBIUM PENTOXIDE SUPPLIERS

Materials Handbook

activated or completely activated; the most popular is RMA (rosin, mildly activated).

peratures without a shortening of the firing range. Ceramic grades of petalite are available in commercial quantities.

PERICLASE. Natural MgO used in refractories. (See MAGNESIA.)

PHOSPHATES. A mineral compound characterized by a tetrahedral ionic group of phosphate and oxygen, PO43-.

PERICLASE SUPPLIERS PHOSPHATE SUPPLIERS H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

O

LIVINE. Mineral containing a mixture of forsterite (Mg2SiO4) and fayalite (Fe2SiO4) in solid solution. Olivine is the principle component of the rock dunite. It’s primarily used in applications involving hot metal. Olivine was first used as an industrial mineral as a refractory in the early 1930s. Initially, it was introduced as hand-cobbed, selected, shaped blocks of crude olivine. More recently, finely ground olivine blended with MgO and pressed into brick has found use in glass tank and open hearth furnaces. Ramming or gunning mixes for basic furnace linings also utilize olivine. In Europe, and to a limited extent in the United States, olivine is used as a refractory brick for night storage heaters. All U.S. olivine is produced in Washington or western North Carolina. Relatively clean olivine has a PCE of 33-35. ORGANOMETALLICS. Of interest to the ceramic industry are those organometallics, the hydroxide-free alkoxides, which can be used for the vapor-phase synthesis of hard ceramic oxide coatings, films or free-standing bodies. Very fine particulate oxides also can be formed from these chemicals. Compounds now available include aluminum isoproproxide, aluminum hexafluoroisoproproxide, lithium hexafluoroisoproproxide, sodium hexafluoroisoproproxide, zirconium hexafluoroisoproproxide and zirconium tertiary amyloxide.

P

ASTES. Conductor, resistor, dielectric, seal glass, polymer and soldering compositions are available in paste or ink form. Often called thick film compositions, the materials are used to produce hybrid circuits, networks and ceramic capacitors. Conductor pastes consist of metallic elements and binders suspended in an organic vehicle. Primarily, precious metals such as gold, platinum, palladium, silver, copper and nickel are used singularly or in combination as the conductive element. The adhesion mechanism to the substrate is provided by either a frit bond, reactive bond or mixed bond. During drying, usually at ~125°C, the vehicle is removed. Further processing is done through free-air-flowing tunnel kilns at 550-1000°C. Fired film thickness is 2-20 μm. Important properties of conductor pastes include wire bondability, conductivity, solderability, solder leach resistance and line definition. Thick-film resistor pastes are composed of a combination of glass frit, metal and oxides. Resistor pastes are available in values ranging from 0.2 ohm/sq to 10 M ohm/sq, and in firing temperatures from 600-850°C. Temperature coefficient of resistance can vary from 40-150 ppm/ºC. These pastes are used in microcircuits, voltage dividers, resistor networks, chip resistors and potentiometers. Dielectric compounds are used as insulators for the fabrication of multilayer circuits, crossovers or as protective coverings. Solder pastes are one of the more common component adhesion products. They consist of finely divided solder powders of all common alloys of tin, lead, silver, gold, etc., suspended in a vehicle-flux system. The fluxes may be non-

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ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com PEROVSKITES. Ceramic oxides of the general formula ABO3, where A is a large-sized cation of low charge and B is a small highly-charged cation. Used in many magnetic, electrical, optical or piezoelectric applications. PETALITE. (Lithium-aluminum silicate.) Li2O-Al2O3-8SiO2. M.p. 1400°C max; density 2.4 g/cm3. Contains 77% SiO2, 17.5% Al2O3, 4.3% Li2O and 0.5% other alkalies. The high lithia:alumina ratio and very low content of other alkalies, which is comparable to spodumene, makes it ideally suited for lithium additions in porcelain enamels and glasses. Its solubility has been observed not to have any effect on the set of enamel slips. Petalite can be added up to 45% in semifritted dinnerware glazes, resulting in a clear, bright texture maturing at cone 02-5. Petalite is effective in clear and opaque, raw single-fire glazes to cone 12. Thermochemical behavior: When natural petalite is heated above 1000°C, there is an irreversible crystallographic inversion into a solid solution of silica in beta spodumene. This unique structure has virtually zero thermal expansion and provides the basis for low expansion ceramic bodies of unexcelled heat shock resistance. Within the lithia-alumina-silica system there exists a broad compositional area of low-to-zero thermal expansion. Negative expansions (the bodies actually contract upon heating) are encountered in certain areas. Such bodies can, of course, be synthesized from pure chemicals and a wide variety of expansion characteristics can thus be obtained. Because of this behavior, petalite can be added to refractory mixes to improve their resistance to thermal shock. Such additions lower the PCE of the refractory body, but result in much longer life of refractories subjected to repeated severe temperature changes. Other lithium-bearing ores, such as amblygonite and spodumene, can be used in the same manner. The advantage of petalite in specialty bodies lies in the fact that it permits relatively low expansion bodies over a wide composition range at a fraction of the cost of synthetic bodies based on pure chemicals. Practical bodies of simple clay-petalite mixtures can be formulated with linear expansions from 4.5 x 10-6 linear to 0 or slightly negative values. Minor additions of petalite in whiteware bodies—principally at the expense of flint—lessen the quartz inversion hump. The advantages of a more straight-line expansion curve are: (1) the tendency to dunt is lessened and ware losses decreased; (2) the cooling cycle in the bisque firing cycle can be shortened, with an attendant increase in production; (3) for certain products, such as electrical porcelain, an improvement in thermal shock resistance is desirable in the finished product; and (4) the reheat portion of glost or refiring cycles can be increased to normal bisque rates. Synthetic petalite melts at 1356°C; PCE of the commercial mineral is cone 15. Because of its high PCE, petalite is not of interest as a principal flux in conventional whiteware bodies. However, it is of considerable interest as an auxiliary flux since it forms low melting eutectics with both feldspar and nepheline syenite. Petalite can be employed to lower maturing tem-

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BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com PIGMENTS. Solid powders used to give black, white or other color to bodies and coatings by reflecting the light of certain wavelengths and absorbing the light of other wavelengths. PIGMENT SUPPLIERS

MASON COLOR WORKS INC. 250 E. Second St., Box 76 East Liverpool, OH 43920 (330) 385-4400 Fax: (330) 385-4488 Email: [email protected] Website: www.masoncolor.com SHEPHERD COLOR 4539 Dues Dr. Cincinnati, OH 45246 (513) 874-0714 Fax: (513) 874-0946 Email: [email protected] Website: www.shepherdcolor.com PIEZOELECTRIC COMPOSITIONS. Piezoelectric ceramic compositions are characterized by high stability with temperature and time in resonant frequency and by high electromechanical coupling coefficients and high dielectric constants, or by high electromechanical coupling coefficients and high mechanical quality factors. PIEZOELECTRIC COMPOSITION SUPPLIERS APC INTERNATIONAL LTD., AMERICAN PIEZO CERAMICS P.O. Box 180, Duck Run Mackeyville, PA 17750 (570) 726-6961 Fax: (570) 726-7466 Email: [email protected] Website: www.americanpiezo.com MORGAN TECHNICAL CERAMICS 232 Forbes Rd. Bedford, OH 44146 (440) 232-8600 Fax: (440) 232-8731 Email: [email protected] Website: www.morganelectroceramics.com PLASTER. Plaster is a material similar to mortar or cement, in that it begins as a dry powder and is mixed with water to form a paste. The paste then hardens somewhat and can be easily manipulated with metal tools or even sandpaper. Source: Wikipedia, http://en.wikipedia.org/wiki/Plaster

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2012 Edition

PLASTER SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com PLASTER OF PARIS. (Calcined gypsum.) CaSO4-0.5H2O. A white, gray or pinkish-colored powder prepared by heating gypsum (CaSO42H2O) to remove 75% of its water of crystallization. Available in various types of products having specific, controlled properties. When mixed with water and allowed to rehydrate to the dihydrate (CaSO4-2H2O), there is no apparent action at first, but soon a slight stiffening takes place and shortly after that it “sets” to a solid mass. As set progresses the mass begins to heat and expand, and final set is not reached until the evolution of heat has ceased and expansion is complete. Through changes in the manufacturing process, the time of set can be varied widely (from a few minutes to many hours), and linear setting expansion also is controllable from 0.05%-2.0%. The normal linear setting expansion of pottery plasters is ~0.20% in all directions if the cast is unconfined, but under conditions of confinement, all the setting expansion may take place in one direction only. Under conditions of partial confinement, warping, twisting, or slight crushing of surface or internal structures can develop. The stresses set up by the setting expansion forces are usually relieved rapidly by cold flow in the set plaster before drying. When this occurs, the magnitude of expansion is not accurately predictable and must be obtained by measurement. Plasters are used in a variety of ceramic industry applications: 1. In a limited way, as chemical additives to glazes, supplying neutral, slightly soluble calcium and sulfate sulfur. 2. As a glass batching material to replace part or all of the salt cake when combined with soda ash in proper proportions. Here, use of plaster eliminates salt water scumming, retaining the desirable fluxing property of salt cake. It appears that gypsum is going to be widely used as a source of sulfur. The basic problem here is to obtain an inexpensive material (as compared with barium sulfate) that will furnish sulfur dioxide upon decomposition. Apparently, SO2 gas aids in clearing up the glass and in giving added brilliance. 3. As a bedding and leveling agent in grinding and polishing plate glass, plaster cements the glass to the grinding bed during the operation while also being easy to remove from the glass surface. Its soft crystal is not abrasive to glass surfaces. 4. Optical glass mounting. Used to retain optical glass, lenses, prisms and oculars in position while surfaces are formed to the desired curves by grinding and polishing. Also used in setting levels and bubble glasses in position where permanent positioning is desired. 5. Model making. Used in the ceramic industry generally for preparing original models. Remains permanently without dimensional change or surface corrosion. Set blocks of plaster have a grain-free structure which permits carving or cutting in any direction without difficulty, and advantage may be taken of the plastic period prior to set for template forming. Various types of models are used for foundry patterns directly, for master patterns, for diemaking operations im metals, etc.

PLASTER

6. Metal mold making. When suitably compounded with refractory substances, molds for the casting of nonferrous alloys, such as white metal, brass, aluminum alloys, etc., are made with plaster. 7. Low-density insulation. Used to provide green strength to mixtures of clays, nonplastic refractories and organics. 8. Potter mold and die making. This use constitutes the principal ceramic application of plasters. Newer plasters are commercially available, which, while having identically the same chemical composition as other plasters, require much lower amounts of mixing water to form a pourable mix. This characteristic is due to the manufacturing processes that differ from those used for ordinary plasters. Two types of these super-strength gypsum plasters are commercially known. One type is made by calcination under steam pressure, while the other is calcined in a chemical solution. The steam calcined material requires approximately 25% more mixing water than the chemically calcined gypsum to yield a pourable mix. As a result of this property, the chemically calcined material gives a much stronger, denser cast. A number of products are made with these materials, the important characteristics of which are high compressive strength, resistance to wear and low expansion in the finished mold. These super-strength plasters are called alpha gypsum to differentiate them from regular plasters (beta gypsum), which have a somewhat different crystal structure in the calcined state. Regardless of the plaster used, 100 lb of HEMI hydrate (CaSO4-0.5H2O) requires just 18.6 lb of water to react to dihydrate (CaSO4-2H2O). Water in excess of the chemical requirement is always necessary to obtain fluidity, however, and when this is removed by drying, numerous empty pores result. The effects of the decrease in density accompanying increasing water additions are reductions in compressive strength, hardness and wear resistance. Decrease in density does, however, result in greater water absorption in the mold, and the minimum permissible absorption usually governs the water-to-plaster ratio used. In general, working molds should be made with the lowest water-to-plaster ratio (consistency) that is compatible with plant conditions. It is important to note that at a given density the hardness, strength and abrasion resistance of a mold are greatly reduced by the presence of free water. Compressive strength, for example, is usually about half as much for a damp mold as for the same mold when dry. The requirements for a block-mold material are somewhat similar to those of a model material because carving is often essential. Since the block mold is generally used to make a few check casts in clay, it must be sufficiently durable and absorbent to lend itself to this use. Case Molds: In the production of case molds, the principal requisites of a good material are: (1) extremely low setting expansion to prevent binding in or warpage of the block mold; (2) a low normal consistency that will provide a hard, smooth surface and high strength (possession of these characteristics makes sizing easier, prevents excessive case mold wear, prevents sticking of the working mold to the case mold and results in well-fitting working molds); (3) a low normal consistency so that fine detail may be duplicated accurately without the necessity of sacrificing strength to obtain high fluidity; (4) a sufficiently long period of plasticity to enable the mold maker to trim the mold exterior before final set occurs; and (5) dimensional stability throughout a long storage period without loss of surface perfection. Jigger and Casting Molds: The requirements of a working jigger or casting mold are that it accurately reflects the model, produces good ware having uniform density and neither pinholes nor high spots, and provides long, economical service. The specific demands made on a plaster for working molds are: (1) low normal consistency so that slurries for the densest molds may be easily mixed and poured without pin-

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PLATINUM

holes or loss of details; (2) moderate but uniform expansion so that, while the working mold will free itself from the case mold easily, it will not bind or warp, will fit the jigger ring, and will attain an accurate, predetermined size and shape; (3) sufficiently long and uniform period of plasticity to enable the mold maker to complete pourings without haste and to plan work with the assurance that the length of the plastic period will not change from mix to mix; (4) sufficient regularity in physical properties of the calcined gypsum that many molds may be made over a period of years without significant variations in mold characteristics; and (5) the ability to make molds that wear slowly and evenly, absorb water uniformly and, at the same time, have sufficient strength to resist ordinary abuse. In practical mold making, uniformity and careful control of procedures by the user are of the greatest importance for best performance of any plaster. Factors that must be standardized and kept nonvarying are: consistency (waterto-plaster ratio); mixing (time and method); and clay shop handling methods, environment and conditions of use. Chemical Action of Clay on Mold: When sodium silicate and carbonate of soda are used in the slip, the mold will effloresce. There is no absolutely certain way of preventing this, as it is due to the reaction between the sodium carbonate (soda ash) or silicate with the gypsum in the mold itself, forming insoluble calcium carbonate and calcium silicate and soluble sodium sulfate. This sulfate of soda is carried to the surface of the mold by the water absorbed from the slip. As it reaches the surface, it evaporates, leaving behind the sulfate as a white powder, the efflorescence. Wherever such chemicals are used in the slip, efflorescence is bound to occur. This can be remedied somewhat by placing the mold during drying in such a position that the evaporation will take place from the back of the mold. The soluble salts are thus drawn, by capillarity, away from the face of the mold. The use of organic dispersing agents in place of sodium silicate or carbonate will obviate this trouble. For maximum mold life, deflocculants should be used in the minimum quantity required to obtain proper slip characteristics. Also, when sodium carbonate and sodium silicate are employed in combination as a deflocculant, the amount of carbonate should be reduced to the absolute minimum permissible. Silicate in general has a less eroding effect on mold surface than carbonate, and indications are that 50% greater mold life is obtainable with sodium silicate as compared with carbonate. PLASTER OF PARIS SUPPLIERS ALLIED CUSTOM GYPSUM 1550 Double Dr. Norman, OK 73069 (405) 366-9500 Fax: (405) 366-9515 Email: [email protected] Website: www.alliedcustomgypsum.com PLATINUM. Pt. At. wt. 195; sp. gr. 21; m.p. 1755°C; softens at temperature well below its melting point, volatilizes at 4050°C. Metallic element soluble in aqua regia and fused alkali, insoluble in water and ordinary acids and alkalies. Mined in Alaska, California, Canada, the former USSR, South Africa and Colombia. Platinum is sometimes used in glazes to obtain luster and metallic effects. Liquid bright platinum and liquid bright palladium (an element of the platinum group) are preparations used in metallic decorations. As platinum produces a better silver effect than silver itself and is less likely to tarnish, platinum is preferred to that metal. A luster produced from a strong solution of platinum chloride and spirits or oil of lavender upon firing gives a steely appearance which is nearly opaque. Another method consists of precipitating the metal from its solution in water CERAMIC INDUSTRY ³ January 2012

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POTASSIUM TITANATE

by heating it with a solution of caustic soda and glucose. The metal is mixed with 5% bismuth subnitrate, applied to the ware by painting and fired in a reducing atmosphere. POLYACRYLAMIDE. Polyacrylamide is a polymer (-CH2CHCONH2-) formed from acrylamide subunits that can be readily crosslinked. Souce: Wikipedia, http://en.wikipedia.org/wiki/ Polyacrylamide

POLYACRYLAMIDE SUPPLIERS ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com POTASH. K2O. Mol. wt. 94.2; sp. gr. 2.32; very soluble in water and other solvents. The most important original source of commercial potash is natural potassium salts, which are mined in New Mexico, California, Canada, Germany, France and the former USSR. These are prepared as potassium nitrate and potassium carbonate for use in ceramics, but most of the potash is automatically introduced into batches in feld-soda glass, this being especially true with the use of manganese, nickel oxide and selenium. In the potash glasses, much less cobalt oxide is required in connection with manganese to secure a good neutral tint for crystal glass. Likewise, nickel is a suitable decolorizer for glasses high in potash, whereas its effect in the soda glasses is decidedly ugly. The alkali content of commercial glasses runs about 15% in window glass, 15-17% in container glass and 20% in thin blown glass. Most of the alkali is soda, and while a higher potash content is often desirable, its greater cost limits its wider application. The growth of the American potash industry may allow a price reduction which will make this material more available to glass manufacturers, who now limit its general use to the more expensive glass products. In optical glass, a ratio of 7 parts potash to 3 soda gives good durability and color to a number of commercial compositions, in which the total potash content of the glass may vary from 7-16% for some crown types. It probably is not possible to derive a potash-soda ratio suitable for all optical glasses. Some high-lead glasses, for example, contain no soda at all, yet show high durability. The discoloring effect of ferrous iron is much less noticeable in a potash-soda optical glass than in a high-soda glass. It has been found that glasses containing both Na2O and K2O gave lower thermal conduction than either alone; the minimum conductivity being obtained with a potash:soda ratio of 4:1. This factor is becoming increasingly important in view of developments in fiberglass. The National Institute of Standards and Technology (NIST, formerly NBS) reports that soda-lime glasses are unstable photochemically, whereas potash-lime glass is not appreciably affected by ultraviolet radiation. The behavior of colorants in colored glass is often superior in potash glass to that in spar. In enamels the alkali content averages 10% in sheet ground coats, 20% in cover coats, 15% in cast iron enamels, and as much as 36% in jewelry enamels. In the last type, all of the alkali is potash, which is believed to increase brilliance and luster, but in other enamels all or most of the potash is merely accessory to alumina in the addition of feldspar. The same may be said for the potash content of glazes. As a flux in glazes, potash is only about 85% as active as soda. If present in excess, K2O may cause peeling and crazing if the other constituents are not in suitable proportions. Potash is reported not as conducive as soda to the formation of crystals in crystalline glazes. Potash in the hydroxide or carbonate form is an important deflocculating agent. It is used at ordinary

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temperatures to prepare casting slips, glaze slips and engobes; to purify clay; to reduce the plasticity of excessively plastic clays and to neutralize any acid present. (See POTASSIUM CARBONATE.) POTASSIUM CARBONATE. (Pearl ash, potash.) K2CO3. Mol. wt. 138.2. Although formerly imported, all domestic requirements at present are being supplied by American producers who distribute a product made by the electrolysis of potassium chloride from deposits located in California and New Mexico. In glass manufacture, potassium carbonate is supplied in both calcined and hydrated form. The product sold to the glass industry is easy to handle, being of granular particle form, and has entirely eliminated the dusty material, formerly supplied from abroad, with its irritating handling problems. The present domestic materials are supplied with very low chloride and sulfate content and are entirely suitable for all types of glass production. Although the viscosity of the potash glasses is high, thus making them somewhat difficult to work, the viscosity is easily remedied by introducing lead oxide. Hence, the combination of potash and lead oxide leads to the production of a glass which lends itself well to handworking. This combination possesses a long working range. All of the potash glasses, which from their nature must be melted in closed pots, exert a different sort of corrosive action on the clay wall from that exhibited by soda glasses. The corrosion by soda glass proceeds quite smoothly, but the potash glasses produce a honeycombing or pitting effect, and the thin partitions between these pits, finally reduced to small pinnacles, float out into the glass, forming stones. It seems to be an almost unavoidable characteristic of the potashlead glasses to produce a great deal of stony ware. In its influence on the physical properties of glass, potash does not differ greatly from soda. Compared with soda in equal weight percentages, potash seems to confer a little more density, less hardness and less tenacity. English and Turner rate its factor for coefficient of expansion at 11.70 as compared with soda at 12.97. The two are by far the most expansible oxides in glass. In glazes potassium carbonate appears as an ingredient when it is desirable to modify the effect of a colorant such as copper oxide, which may thus be brought through tints of green toward yellow. This formula gives a clear green glaze at cone 2:

}

CaO 0.45 CuO 0.10 K2O 0.15 PbO 0.30

Al2O3 0.20 { 2SiO2 1.60

When potassium carbonate is used in glazes in combination with sodium oxide, lead oxide or calcium oxide, the potassium oxide derivative cannot exceed 0.15 equivalent without affecting the color. If the foregoing glaze composition were modified by decreasing CaO to 0.30 equivalent and increasing K2O to 0.30 equivalent, a brilliant robin’s egg blue is achieved at cone 2-3. When potassium carbonate is used in colored glazes, it is advisable to frit about 90% of the clay, but none of the color. In enamels potassium carbonate tends to produce high luster, but it decreases strength and elasticity, making the enamel soft. In general, enamels containing potassium are more readily fusible than those with sodium. Potassium carbonate has largely been replaced in enamels, however, by sodium carbonate, due to the difference in price, except in occasional cases where it is used to alter colors, as discussed.

gration at ~400°C. Prepared by the interaction of sodium nitrate and potassium chloride. Potassium nitrate is used in glass, glazes and enamels mainly because of its powerful oxidizing and fluxing value. Most enamels contain some oxidizing agent in the form of potassium or sodium nitrate. Only a small amount of nitrate is necessary, 2-4% being sufficient to maintain oxidizing conditions in most smelting operations. It is highly important that sufficient oxygen be present to prevent reduction of easily reducible compounds in the batch, especially lead or antimony. High antimony oxide enamels should contain sufficient oxidizing agents, and about double the amount of nitrate is suggested. If the antimony is allowed to go into solution, its opacifying power is lost and the color of the enamel is destroyed. When the batch is fairly oxidizing, as much as 0.1% red oxide of iron can be incorporated in a white enamel without any serious damage to the color. While blue, black and dark colors can be produced under oxidizing conditions, they will be produced more cheaply and easily under reducing conditions. Enamels without any niter melt with much less frothing than those containing it in sufficient amounts to maintain an oxidizing environment. Excessive niter should be avoided because it is expensive. No benefit is derived from using it as a flux, other than in an alkaline form, because it increases the difficulty of melting. In glazes it is sometimes used as a flux in place of potassium oxide, but, owing to its cost and solubility, very little of it is contained in glaze. Where conditions prevent the use of sufficient potash feldspar, potassium oxide is introduced into the mix, usually in the form of the nitrate in a frit. POTASSIUM NITRATE SUPPLIERS SQM NORTH AMERICA CORP., INDUSTRIAL 2727 Paces Ferry Rd. S.E. Ste. 2-1425 Atlanta, GA 30339-6160 (770) 916-9426 Fax: (770) 916-9401 Email: [email protected] Website: www.sqm.com POTASSIUM TITANATE. A solid-state reaction is used to produce potassium titanate. These powder products are commonly used for fluxes and arc stabilizers in welding rod and wire. The advantage of potassium titanate over other welding rod powders is the effect of the TiO2 (a slag former) and K2O (arc stabilizer), which, in combination, provide good slag flow and sustained arc stability. This results in cleaner welds, better overall metallurgical properties, and improved weld uniformity. Potassium titanate is also used in the friction industry as an additive to brake pad formulations. As a friction modifier, the material can be produced in various morphologies to provide specific properties in thermal transfer and wear, including potassium titanate whiskers, platelets, and finely milled powder. Potassium titanate whiskers are used in the plastics industry as reinforcing fibers in many thermoplastic composite materials, including PEEK and PTFE. A potassium titanate whisker-reinforced thermoplastic composite is suitable to fabricate precision injection parts with complex shapes or thin walls, has better flow properties and less damage to processing equipment. The products made from the composite particulates can provide many beneficial characteristics, such as higher tensile strength, corrosion resistance, abrasion resistance, chemical and thermal stability, and better surface quality.

POTASSIUM NITRATE. (Niter, saltpeter.) KNO3. Mol. wt. 101; sp. gr. 2.1; m.p. 334°C; very soluble. Decomposes with defla-

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POTASSIUM TITANATE SUPPLIERS

TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net POTASSIUM TITANATE, FIBROUS. Potassium titanate fibers provide good chemical stability, heat resistance and friction properties in applications ranging from automotive brakes and other components to paints and insulation materials. POWDER BLUE. (See COBALT OXIDE.) POWDER COMPOUNDS. A substance made of two or more dry particles that is chemically combined in a specific ratio. POWDERED METAL. (See METAL POWDERS.) POWDERED METAL SUPPLIERS

POTASSIUM TITANATE

PREPARED CERAMIC BODY. A ceramic body comprises all the minerals needed to make ceramic items (clays/ fluxes/fillers) and is available in forms ready for use in the manufacturing process. Forms include slurry, granulate or plastic-extruded. High Al2O3-containing bodies are also available that conform to the standard C 786, C 795 and C 799 of DIN 60672-1 with 92%, 94%, 96% and 99% Al2O3. These ready formulated raw materials are ready for pressing and can be formed directly into ceramic tiles via axial or cold isostatic pressing. (See ALUMINA BODIES.) PREPARED CERAMIC BODY SUPPLIERS IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected]

H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

PUMICE. Pumice is a type of extrusive volcanic rock, produced when lava with a very high content of water and gases is extruded from a volcano. As the gas bubbles escape from the lava, it becomes frothy. When this lava cools and hardens, the result is a very light rock material filled with tiny bubbles of gas.

H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

PUMICE SUPPLIERS

POWDERS, AIR PLASMA SPRAY. Typically ceramic powders used to produce temperature- and wear-resistant coatings via thermal or plasma spray processes. POWDERS, AIR PLASMA SPRAY SUPPLIERS PHOENIX COATING RESOURCES INC. P.O. Box 1439, 2377 S. R. 37 S. Mulberry, FL 33860-1439 (863) 425-1430 Fax: (863) 425-1524 Email: [email protected] Website: www.phoenixcoatingresources.com PRASEODYMIUM OXALATE. Pr2(C2O4)3. Used in electronic ceramics and glass compounds. Also used as a coloring agent. PRASEODYMIUM OXIDE. Pr6O11. Mol. wt. 1021.5; m.p. 2200°C. Soluble in strong acids and slightly soluble in water. As ordinarily prepared by calcining in air, praseodymium forms the black oxide Pr6O11. In its other compounds, it exists in a form comparable to Pr2O3 (mol. wt. 329.8). Praseodymium, a rare earth, occurs in monazite and bastnasite. It colors glass a distinctive green. Its oxide and compounds are available in purities up to 99.9%. Praseodymium oxide came into use in a brilliant yellow ceramic color based primarily on zirconia and silica. The color is compatible with pinks and blues, is unaffected by glaze composition and is stable at ordinary glaze temperatures. Suitable for use with some oven heating elements.

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com PYROLYTIC GRAPHITE. A high purity form of carbon (C) produced by thermal decomposition of carbonaceous gases. The commercial manufacture of pyrolytic graphite products is a relatively new division of the graphite industry. Though this material has been known for some 50 years (glance coal, deposited carbon in gas retorts, etc.), it is only within the last 10-15 years that the necessary production techniques have been developed. The manufacturing process essentially consists of bringing a relatively cold, carbonaceous gas into contact with a heated surface (mandrel) and thus extracting the carbon, in the form of graphite, directly from the gas. This process is not to be confused with the pyrolysis of resins and pitches which is involved in the manufacture of the more common bulk or polycrystalline graphites. The formation of pyrolytic graphite directly from a hydrocarbon gas results in a structure which is distinctly different from other commercial forms of this element. While polycrystalline graphites consist of at least two solid phases (binder and filler) and are porous to varying degrees, pyrolytic graphite consists of a single phase (no binder) and is essentially impervious to gases. By properly designing furnace hardware and controlling the deposition process, pyrolytic graphite can be manufactured commercially as solid plate, cones, tubes and other free-standing shapes. Because the deposition process relies, in part, on diffusion of the hydrocarbon gas to the

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PYROPHYLLITE

heated mandrel, it also is possible to densify porous structures of carbon or graphite by infiltration with pyrolytic graphite. This infiltration procedure is presently the basis for considerable commercial activity. As with other materials, pyrolytic graphite can be manufactured with a variety of different properties. By employing deposition temperatures of 1000-2500°C, it is possible to generate pyrolytic graphites with densities of 1.2-2.20 g/cm3 or higher. Further heat treatments and pressure annealing can increase the density to values approaching the theoretical density of graphite (2.26 g/cm3). Deposits formed at lower temperatures are generally referred to as pyrolytic carbons and are relatively isotropic and of low density. High temperature deposits of pyrolytic graphite are of higher density and are very anisotropic. The anisotropy of well-ordered pyrolytic graphite is attributable to the fundamental structure of graphite. A simple analogy can be drawn between a piece of pyrolytic graphite and a deck of cards. Each card, or plane of graphite, is composed of a two-dimensional network of carbon atoms bonded together in the form of hexagons. Within these planes (called basal planes), the carbon-carbon bond strength exceeds that in diamond. However, there is no equivalent bonding between the planes or sheets of carbon atoms and, in fact, the stack of planes is held together primarily by the rather weak, van der Waals’ forces of attraction. With this layered structure, the thermal and electrical conductivity of pyrolytic graphite is very high parallel to the planes but much lower in the direction perpendicular to the planes. This directionality is so great that a well-ordered pyrolytic graphite may have a thermal conductivity equal to copper in the planar (a-b) direction, while it is essentially an insulator in the direction perpendicular to the planes (the c direction). Advantage is taken of this anisotropy when pyrolytic graphite is employed for rocket nozzles, missile nose cones and other applications where conductive anisotropy is desirable. The structure of pyrolytic graphite also accounts for the fact that this material can exhibit tensile strengths of 20,000 psi in the a-b direction, while in the c direction the tensile strength is about 1500 psi. As with other graphites, the pyrolytic form displays higher strengths at elevated temperatures, does not melt under normal pressures and sublimes above 3500°C. Pyrolytic graphite is much more resistant to oxidation than ordinary polycrystalline graphites because the attack by oxygen occurs at the edges of the basal planes, which comprise less of the surface of a piece of pyrolytic graphite. In addition, pyrolytic graphite is essentially impervious to oxygen and, therefore, internal oxidation is minimized. The commercially available forms of pyrolytic graphite include plate stock, tubes and free-standing shapes. In addition, pyrolytic graphite is used commercially to densify porous structures such as carbon felts, fabrics, composites of carbon/ graphite yarns and that can withstand the deposition temperature and are compatible with pyrolytic graphite. It also is used to coat conventional (bulk) graphites where increased resistance to oxidation and chemical attack are desired. In the past, pyrolytic graphite has been used primarily in those areas where its high cost was offset by the unique properties of this material. Today, however, as this technology comes of age, pyrolytic graphite is being used in an increasing number of applications within industry. PYROPHYLLITE. Al2O3-4SiO2-H2O. One of the rather large family of hydrous aluminum silicates. Often confused with talc, as the two minerals have almost identical physical properties. However, pyrophyllite is an aluminum silicate, whereas talc is a magnesium silicate. It is very soft, with hardness of 1-2 Mohs scale and specific gravity of 2.8-2.9. It is found in North Carolina, Pennsylvania, California and Newfoundland.

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PYROPHYLLITE

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RARE EARTHS

In the Carolinas, pyrophyllite occurrences are restricted to a belt of rocks known as the Volcanic Slate Series, which lies northeast and southwest across the eastern Piedmont section. All of our known pyrophyllite occurrences in the Carolinas are within this type of rock; none are known outside of it. Three chief types of pyrophyllite are found in nature: (1) the micaceous, or flaky variety, known as foliated pyrophyllite; (2) the star-like or flower-like variety-crystalline or radiating pyrophyllite; and (3) the compact, homogenous variety, known as massive pyrophyllite. Of these, the massive variety is the type chiefly used in the manufacture of refractories. Since the foliated variety makes flat, slabby grains when crushed to refractory grain size, and often carries considerable alkalies which act as a flux, it is not considered a good refractory raw material and is used chiefly as a filler and ceramic raw material. The radiating type is used in small amounts in the refractory trade, but large amounts are objectionable, due to excessive expansion or exfoliation and the long needle-like shape of the grains which reduces their strength. Thus, the massive type has all of the good characteristics of pyrophyllite as well as a strong, rounded particle when crushed to desired size for use in refractories. This makes it the most desirable ore type for use in refractories. Pyrophyllite has been used successfully in the manufacture of a wide variety of refractory products: fire brick, metal pouring refractories, castables, plastic and gunning mixes, and kiln car refractories, for example. Perhaps its best known property is its characteristic of expanding on heating. For this reason, pyrophyllite offers several advantages in refractory specialties. First, it eliminates the need for a calcining operation required by certain fireclays. Further, this expansion tends to counteract the shrinkage of the plastic fraction of the mix so that a plastic refractory may be obtained which is essentially of equal volume before and after drying and firing. Experience has shown that when properly made and used, pyrophyllite refractories have good spall and slag resistance. However, it has also been shown that they should not be used in contact with slags that are strongly basic. Pyrophyllite has this theoretical composition (in %): 67.7 silica, 28.3 alumina, 5.0 combined water. From the high silica content of the mineral, one would expect it to possess excellent volume stability at elevated temperatures. Pyrophyllite-clay compositions have shown good volume stability when subjected to repeated reheat shrinkage cycles at temperatures of 2460 and 2640°F. Pyrophylliteclay compositions also have shown excellent resistance to deformation under load at high temperatures in 100-hr hot load tests. Almost no deformation takes place. Pyrophyllite has several other characteristics which make it suitable for use in refractories; namely, it has a sufficiently high PCE to be considered a refractory; it can be mined at a sufficiently low cost for commercial development; and, in addition, bodies made by the stiff-mud process have the unusual property, which no fireclays possess, of practically zero shrinkage or expansion in firing. Because of this almost unique characteristic (reversible thermal expansion), pyrophyllite was found adaptable to the manufacture of an unfired refractory. Pyrophyllite usually occurs with varying amounts of associated minerals such as quartz, sericite, chlorotoid, pyrite, chlorite, feldspar, hematite, and magnetite. The ores used for refractory work are chosen so as to eliminate as many of these as possible at the mine. In addition, the different grades as mined are blended at the plant to form a uniform feed from which refractory grog is made. It has been found that certain maximum and minimum amounts of associated minerals may be tolerated in pyrophyllite to be used for refractories. Blending of the various ores, as mined, is carried out at the plant to produce a uniform grog which adheres as closely as possible to these requirements. The pyrophyllite

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content of 80-85% corresponds to an Al2O3 content of 23-25%. It has been found recently that, quite often, small amounts of high-alumina minerals occur with the Carolina pyrophyllite deposits. Kyanite, andalusite, topaz and diaspore have been identified with the Carolina deposits. These are not considered objectionable. In fact, in small amounts, they tend to raise the alumina content of the ores by several percentage points. This raises the PCE value without substantially altering the desirable properties of the pyrophyllite. Substitution of pyrophyllite for part or all of the flint or feldspar in a wall tile body caused a decrease in thermal expansion, with resultant decrease in tendency of both body and glaze to fall when subjected to sudden temperature changes. Detailed study of the material in wall tile bodies showed it can: increase the firing range, decrease crazing due to thermal shock or moisture expansion, decrease firecracking, decrease shrinkage with a resultant decrease in warpage, and decrease wear on molds and dies. In electrical insulator bodies, pyrophyllite has been used with success in very large amounts. Bodies containing 94-96% pyrophyllite compare favorably with porcelain in mechanical and electrical characteristics and may be used in applications where high puncture values or zero porosity are not required. They were superior to porcelain for certain high-frequency applications, but not as good as steatite. A relatively new application for the material: seals used in the high temperature, high pressure forming of synthetic diamonds. PYROPHYLLITE SUPPLIERS

R. T. VANDERBILT, CO. INC. P.O. Box 5150 Norwalk, CT 06856-5150 (203) 853-1400 Fax: (203) 853-1452 Email: [email protected] Website: www.rtvanderbilt.com PZT. Lead zirconium titanate, used in piezoelectric transducers. (See also LEAD ZIRCONATE TITANATE.) PZT SUPPLIERS APC INTERNATIONAL LTD., AMERICAN PIEZO CERAMICS P.O. Box 180, Duck Run Mackeyville, PA 17750 (570) 726-6961 Fax: (570) 726-7466 Email: [email protected] Website: www.americanpiezo.com MORGAN TECHNICAL CERAMICS 232 Forbes Rd. Bedford, OH 44146 (440) 232-8600 Fax: (440) 232-8731 Email: [email protected] Website: www.morganelectroceramics.com

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Q

UARTZ. SiO2. M.p. 1713°C. (See FLINT, SILICA, SAND.)

QUARTZ SUPPLIERS IMERYS, NORTH AMERICA CERAMICS 100 Mansell Ct. E, #300 Roswell, GA 30076 (770) 645-3705 Fax: (770) 645-3460 Email: [email protected] Website: www.imerys-ceramics.com UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected]

R

ARE EARTHS. The rare-earth elements collectively account for about one-fifth of the metals occurring in the earth’s crust. Except for promethium, all of the rare earths are more plentiful than cadmium, selenium or mercury. As a group, their general chemical behavior is similar. Rare earths occur as mixtures in many minerals. Economic deposits are based largely on the minerals bastnasite and monazite, and to a lesser extent on euxenite, godolinite and xenotime. Yttrium and thorium are not rare earths, but always occur with them in minerals because their general chemistry is similar to that of he rare earths. Production of yttrium and thorium materials is always associated with production of rare earths. Rare earths are broadly classified as light or heavy mixtures of the lighter or heavier atomic weight members of the group. The largest sources of light rare earths—lanthanum, cerium, neodymium, praseodymium, gadolinium, samarium and europium—are bastnasite and monazite ores. Heavy rare earths and yttrium are extracted from the processing of monazite, and from euxenite, gadolinite and xenotime. Thorium is recovered largely from monazite. Rare earth mixtures have been produced commercially since the late 1890s, first as a byproduct of refining thorium nitrate for making incandescent gas mantles, and since about 1920 as primary products. Mixtures produced from minerals without appreciable rare earth separation contain about 50% cerium, 25% lanthanum, 15% neodymium, 5% praseodymium, and 5% others. As fluorides, they are used in arc carbon cores, as oxides for glass polishes, as metals in mischmetal for lighter flints and alloys, and as chlorides in petroleum cracking catalysts. Other mixtures are “didymium” materials and technicalgrade cerium preparations, made by separating the light rare earth mixture into cerium and cerium-free didymium products. Didymium compounds are used as substitutes for mixed rare earths where cerium content is not critical, in barium titanate electronic ceramics and in glass as a physical decolorizer and colorant. Cerium preparations are used as iron oxidizers in glass and in ultraviolet and infrared absorbing glass. Cerium compounds are used in various glass polishinmg formulations. The rare earths are trivalent in the normal state. Europium, samarium and ytterbium form easily oxidized divalent compounds. Cerium, praseodymium and terSupplier listings indicate paid advertising.

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RARE EARTHS

³

SAMARIUM OXIDE

RARE EARTH SUPPLIERS CONTINUED bium exist in the tetravalent state. The tetravalent compounds are less basic than the trivalent salts, and this property is used to separate cerium from mixtures. Separation of cerium-free rare earth mixtures was formerly done by tedious fractional crystallizations and precipitations. Modern technology uses ion exchange and solvent extraction separation methods to produce both technical and ultrahigh-purity rare earths. Lanthanum oxide is used in low dispersion, high refractive index optical glass and in fiber optic glasses. Praseodymium oxide with zirconia gives a pure yellow ceramic stain. Neodymium oxide is a component of laser glass. Yttrium oxide stabilizes zirconia refractories, and it is a component of YIG, YAG and related garnets. Yttrium compounds are host materials for europium-activated red TV phosphors. Lanthanum and neodymium oxides modify the temperature coefficient of capacitance of barium titanate ceramics. Samarium, gadolinium, europium and dysprosium have high neutron cross sections and are used as nuclear poisons. Samarium-cobalt permanent magnets have the highest coercive force of hard magnetic materials. Yttrium and rare earths are also used in recently developed superconductors. RARE EARTH SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com

TREIBACHER INDUSTRIE INC. 515 Consumers Rd., Ste. 212 Toronto, ON M2J 4Z2 Canada (416) 535-2600 Fax: (416) 535-2602 Email: [email protected] Website: www.treibacher.com REFRACTORY OXIDES. Any of a number of oxides that feature high-temperature and corrosion resistance. (See ALUMINUM OXIDE, HAFNIUM OXIDE, TANTALUM OXIDE, TITANIUM DIOXIDE and YTTRIUM OXIDE.) REFRACTORY OXIDE SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com RETARDERS. Retarders are used to slow down a chemical reaction. RETARDER SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com RHODIUM SESQUIOXIDE. Rh2O3. Mol. wt. 253.82. Amorphous or gray crystals insoluble in water, acids and alkalis. Decomposes above 1100°C.

Table I: Properties of Alkali Metals Property Atomic weight . . . . . . . . . . . . . . . . . . . . . . Density, g/cm3. . . . . . . . . . . . . . . . . . . . . . Melting point, °C. . . . . . . . . . . . . . . . . . . . Important spectral line, angstroms . . . . Ionization potential, gaseous atoms, V5.37 Volume of ions, x 1023/cm3 . . . . . . . . . . .

Lithium

Sodium

Potassium

Rubidium

Cesium

6.940 0.534 186 6707.8 5.12 0.14

22.997 0.97 97.5 5890 4.32 0.37

39.096 0.86 63.7 7664.9 4.16 0.99

65.48 1.53 38.5 7800.2 3.87 1.36

132.91 1.90 28.5 8521.1

Table II: Properties of Rubidium Compounds Property

Carbonate, Rb2CO3

Molecular weight . . . . . . . . . . . . . . . . . . . 230.97 Melting point, °C. . . . . . . . . . . . . . . . . 835 1074 Heat of fusion, kcal/mole . . . . . . . . . . . . — Heat of formation (25°C), kcal/mole Compound. . . . . . . . . . . . . . . . . . . . . . . -269.6 Aqueous . . . . . . . . . . . . . . . . . . . . . . . . 270.0 Specific heat, cal/°C • mole . . . . . . . . . . 28.4 Boiling point (760 mm Hg), °C . . . . . . . . decomposed Heat of vaporization, kcal/mole . . . . . . . — Solubility in water (25°C), g/100 g H2O222.7 48.1

Sulfate, Rb2SO4

Chloride, RbCl

Flouride, RbF

267.02 717 —

120.94 775 4.40

104.48

-340.5 -334.7 — — — 91.2

-102.91 -98.9 12.3 1408 36.92 130.6

-131.28 -137.6 12.2 1381 39.51

4.13

Table III: Properties of Cesium Compounds Property

Carbonate, Cs2CO3

Molecular weight . . . . . . . . . . . . . . . . . . . 325.82 Melting point, °C. . . . . . . . . . . . . . . . . . . . decomposes Heat of fusion, kcal/mole . . . . . . . . . . . . — Heat of formation (25°C), kcal/mole Compouind . . . . . . . . . . . . . . . . . . . . . . -267.4 Aqueous . . . . . . . . . . . . . . . . . . . . . . . . 1278.6 Solubility in water (25°C), g/100 g H2O261.5 179.1

Sulfate, Cs2SO4

Chloride, CsCI

Flouride, CsF

361.88 1019 —

168.37 645 3.60

151.91 682 2.45

-339.38 -335.3 185.8

-103.5 -99.2 366.5

-126.9 -135.9

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1.95

RUBIDIUM. In general, rubidium compounds resemble the compounds of the other alkali metals. However, significant differences are evident because of variation in ionic dimensions, different heats of hydration and the ease with which the outer electron is lost. The reactivity and properties of specific alkali metal compounds depend to a large extent on the properties of the metal or cation involved. Selected properties of the alkali metals are given in Table I. Properties of rubidium compounds are listed in Table II. Cesium has properties similar to the other alkali metals. It is the most reactive member of the group. Because of its greater atomic weight and radius, pronounced differences exist as evidenced by comparing the solubilities of various salts in water and comparing the ionization potentials of the gaseous atoms. Typical properties of cesium compounds are given in Table III. The action of these higher atomic weight alkali metals in glasses is not specifically known. It is quite probable, however, that definite effects will be noticed with such properties as rate of melting, softening point, viscosity, workability, annealing, density and refractivity. The problem of durability also may be influenced. Colors and electrical properties are also known to be profoundly influenced by size and mobility of the alkali cation. One would expect rubidium to react similarly to potassium only more so because of its ionic radius and mobility. Cesium, on the other hand, is very reactive and may show other properties and characteristics. The possible applications of these interesting materials are extremely great in affecting crystal growth or crystal formation, or in modifying glass properties. RUTILE. TiO2. Sp. gr. 4.2-4.3; hardness 6-6.5 Mohs. Usually present as impurities are small quantities of iron oxide, chromium oxide and vanadium oxide. The mineral, an important source of titanium, is mined in Australia, Africa and Florida. In ceramic applications where titanium oxide is desirable (but where a pure white or certain shades are not required) the more economical rutile is frequently substituted for the pure chemical. Rutile is used to stain pottery bodies and glazes in colors ranging from ivory through yellows to dark tan, according to the amount introduced. Artificial teeth are among the ceramics so tinted. One product, mined and milled in Virginia, is reported to be unusually low in Cr2O3 so that it is marketed as an inexpensive substitute for pigment-grade TiO2 in cast iron enamels and in sheet steel enamels not intended for “appliance white.” Rutile is also used in the glass and porcelain enamel industries as a colorant, and to introduce TiO2. The largest use of rutile is as a constituent in welding rod coatings.

S

AMARIUM OXIDE. Sm 2O3. Mol. wt. 348.70; m.p. 2325°C; cubic crystal structure; density 7.43 g/ cm 3. It is slightly soluble in water and soluble in all common acids. A white powder with slight yellow cast, as impurities it contains small amounts of neodymium oxide, europium oxide and gadolinium oxide. Samarium oxide has seven stable isotopes: 3.1%, 15.0%, 11.2%, 13.8%, 7.4%, 26.8% and 22.7%. A 99.9% pure sample of the material, compacted and sintered at 1500°C to 99% of the theoretical density had a modulus of rupture of 2000 psi; modulus of elasticity of 25.6 x 106 psi; and CTE (100-1000°C) of 9.9% x 10-6/°C. The material was unstable in boiling water, but similar bodies fired at 1300°C to 51% of theoretical density were stable in boiling water. Equimolar mixes with Fe2O3 were magnetic and have the advantage over metalic magnetic materials in that they are not conductors.

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SAMARIUM OXIDE

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SELENIUM

Materials Handbook

Sm203 has a high thermal neutron cross section of 5.5 x 10-25 m2/atom, making it usable as a nuclear control rod material. In addition to its muclear uses, it is used in ceramic capacitors, luminescent glasses, infrared absorbing glasses and as a phosphor activator. A major application for samarium metal is in the SmCo5 permanent magnet. (See RARE EARTHS.)

SAPPHIRE. Sapphire has a low coefficient of thermal expansion and an operating temperature above 2000°C, and it measures 9 on the Mohs scale. These characteristics combine to make sapphire a good choice for harsh environments where material failure is unacceptable. Applications include semiconductor equipment components, wafer carriers, wear plates and sputtering targets.

SAMARIUM OXIDE SUPPLIERS

SCANDIUM CARBIDE. ScC. Mol. wt. 56.97. Gray powder, density 3.59 g/cm3. Hexagonal structure, soluble in mineral acids. Has potential as a high temperature semiconductor.

PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com SAND. Has the formula of silica, SiO2, plus whatever impurities are present; iron oxide is usually the most objectionable of these. SiO2 is used in pottery, glass and enamel compositions as silica and flint. (See SILICA and FLINT.) For information on glass sands, see SILICA. SAND SUPPLIERS UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected]

SCANDIUM OXIDE. Sc2O3. Mol. wt. 137.92. A lightweight refractory oxide with m.p. of ~2300°C. Single-crystal density 3.91 g/cm3, cubic structure. Scandium oxide is now prepared in quantity from a variety of sources. Once mostly obtained from minerals such as thortvetite and befanamite, it is now routinely separated from certain uranium tailings. Some recovery from beryllium ores can be expected, plus potential recovery from some phosphate ores with up to 1-2% scandium values. The pure product may be obtained via ion exchange techniques, or via liquid extraction. In the latter, a nitric acid system permits direct evaporation and firing to the oxide. Purities of up to 99.99% are obtained. Major applications lie in high temperature systems and electronic ceramics. In glass compositions, scandium oxide acts as a network former, reducing the density and opening up the structure. It appears to provide better service than high alumina compositions. The oxide can be flame sprayed onto a vari-

High Purity Ground Silica

5 MINING AND PROCESSING LOCATIONS REGISTERED TO ISO 9001 Berkeley Springs, WV t Columbia, SC Mill Creek, OK t Ottawa, IL t Pacific, MO More than 12 different grades Precision ground sizes ranging from 5 to 250 microns Low in moisture, inert and high SiO2 content

ISO 9001

www.u-s-silica.com P.O. Box 187, Berkeley Springs, WV 25411 (304) 258-2500 t Fax (304) 258-8295

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ety of surfaces where it shows heat and thermal shock resistance superior to zirconia, alumina and magnesia. Single crystals of the oxide are superior to sapphire for balance knife edges or laser crystal host matrices. As a transition metal akin to titanium and vanadium, scandium has a third bandwidth sufficient for overlap with neighboring cation orbitals to provide a conduction band. In ferrite formulations, the scandium ion may replace trivalent iron in nickel ferrite. Combined with rare earths and uranium oxides, scandium oxide forms mixed oxides of the type NdScO3. It may also be combined as the orthovanadate, as a titanate, etc. Such compounds as the silicate and phosphates are relatively insoluble and inert. SCANDIUM OXIDE, HIGH-PURITY. Scandium oxide with purity levels of 98-99.99%. (See SCANDIUM OXIDE.) SCANDIUM OXIDE, HIGH-PURITY SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com SELENIUM. Se. At. wt. 79.2; sp. gr. 4.2-4.8; m.p. 217°C; volatizes at 218-687°C, boils at 688°C; insoluble in water and soluble in concentrated sulfuric acid. Semimetallic element of the sulfur group. Selenium is recovered as a byproduct of copper refining in the United States, Canada, Sweden, the former USSR, Mexico and Japan. Selenium is introduced into ceramic compositions as the element itself, as sodium selenite (Na2O-SeO2), or as barium selenite (BaO-SeO2). Sodium selenite has a mol. wt. of 173, is soluble and contains 45.6% Se. Its extremely hygroscopic character is undesirable. Barium selenite has a mol. wt. of 280.6, sp. gr. of 4.75, is only slightly soluble and contains 30% Se. It is a very satisfactory selenium compound for ceramics. The selenites are prepared by converting crude selenium to selenous acid (H2SeO3) by use of nitric acid or by dissolving selenium dioxide in water and then neutralizing the selenous acid solution with a carbonate of the selenite desired. Sodium selenate has a mol. wt. of 173, sp. gr. of 3 and is soluble. Use of the selenate requires a very strong reducing agent (carbon), but the selenite will readily contribute selenium to the batch under ordinary reducing conditions. If these can be maintained, the selenite is preferred to elemental selenium, because the latter burns out to a great extent. Elemental selenium gives the best results in an oxidizing environment, but it is not affected adversely by moderately reducing conditions. Selenium, together with cobalt oxide, furnishes the best decolorizer for tank glass. At one time, due to a selenium shortage, efforts were successful in reducing the selenium normally necessary in the batch for decolorizing a ton of glass to as little as 0.15 oz, which is a satisfactory amount along with 0.05 oz of cobalt. The average today is ~5 oz/ton of glass. These results were obtained by reducing the arsenic, better control of the iron content of raw materials and reducing the sulfates. Proper flame and temperature control also are essential to optimizing use of decolorizer. The behavior of selenium is more constant when the batch contains at least 1 part per 1000 arsenic trioxide as an oxidizing agent. The action of the selenium in the decolorizing process is to produce a pink which is very nearly complementary to the iron green and thereby largely cancels it. Since the color match is not exact, a faint yellow tinge may be left in the glass. Cobalt, therefore, is added to compensate for this yellow. Exposure to sunlight is especially apt to bring out a straw color. This can be removed, Supplier listings indicate paid advertising.

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however, and the original crystal appearance restored, by subjecting the ware to another anneal. When a selenium glass containing Fe2O3 is cooled, a faint pink strikes in the glass in the lehr. For this reason, decolorizing with selenium is not entirely satisfactory for relatively thick and heavy pieces of ware. Properly managed, decolorizing with selenium and cobalt provides the most perfect balance of color for crystal that has thus far been obtained in commercial practice for low and medium-priced ware. Decolorizers for more expensive crystal glass also are being made with cerium oxide. (See CERIUM OXIDE and RARE EARTHS.) Selenium is an important glass colorant. Rose glass is made under mildly oxidizing conditions with a selenium concentration of ~0.05%. The presence of arsenic in the melt, as a stabilizer of oxidizing conditions, is often desirable. However, it gives rise to changes in the lehr when exposed to light. When the element selenium is used in the batch and the melting process proceeds slowly, as in covered pots, there is often a large loss of selenium by volatilization before it can be dissolved and retained. Hence, there is some uncertainty as to the best element because of the variability of the melting processes. In general, much more selenium is required in closed-pot melting than in tank melting because pots generally have more impurities unless special efforts are made to keep them out. Selenium, in combination with cadmium sulfide, is a coloring agent for selenium-ruby glass. A potash-soda batch containing zinc oxide is desirable as it gives better results than a straight soda batch. Good results have been obtained, however, with both types of batches, though selenium tends to produce a brownish cast in soda glasses. The use of potash alone as a flux is ideal as it requires a smaller amount of selenium to color, but the potash-soda combination is less expensive and still gives good results. For producing one of the best colors, a potash-zinc oxide-barium oxide glass is favored. Boron compounds encourage development of the pink color. Ingredients of two typical batches (in lb) follow. Batch A is a softworking selenium ruby; batch B is a cadmium-selenium plate glass batch:

SELENIUM

The glass should be worked as soon as possible after fining, and the temperature should be kept constant at 19002000°F. If the temperature is allowed to rise too high the glass will become seedy, and if it gets too cold it will flash. SEMICONDUCTOR MATERIALS. A solid crystalline material whose electrical conductivity is intermediate between that of a conductor and an insulator, ranging from about 105 mhos to 10-7 mho per meter, and is usually strongly temperature-dependent. Source: McGraw-Hill’s AccessScience Dictionary, http://www.accessscience. com/-Dictionary.

SILANE COUPLING AGENTS. Polymer materials based on Si(OR3), vinyl or amino groups that are used as a pretreatment for reinforcing fibers. Provides strong bonding between the fiber and matrix. SILANE COUPLING AGENT SUPPLIERS GELEST INC. 11 E. Steel Rd. Morrisville, PA 19067 (215) 547-1015 Fax: (215) 547-2484 Email: [email protected] Website: www.gelest.com SILICA. SiO2. Melting points up to 1713°C; softening temperatures 600-800°C. Silica, when foamed, is 99% SiO2 with a bubble structure that is nonconnecting. (See FLINT.) Silicon, next to oxygen, is the most abundant element found in nature. Silica occurs in the crystalline forms

³

SILICA

quartz, tridymite and cristobalite; in cryptocrystalline forms such as chert, flint and chalcedony; and in hydrated forms such as opal. In combination with many of the basic oxides, it forms a very large group of minerals known as the silicates. Silica occurs in a number of crystal forms, the nature and stability ranges of which have been extensively studied. This study has been difficult, partly due to the slow rate at which the changes occur, and the low thermal conductivity of silica and silicates, which tends to mask the results and prevent precise determinations. While tridymite and cristobalite may exist for indefinite periods of time at room temperature, the low-temperature alpha-quartz is believed to be the form of silica truly stable at these temperatures. A considerable expansion accompanies the conversion of _
Selenium amber is made with smaller amounts of selenium than used in ruby glass, and with little or no cadmium sulfide. In making selenium ruby, every care must be taken to keep lead from the batch, as the smallest amount of lead or its compounds will produce a dark liver-colored glass, caused by the throwing down of lead selenide in the glass. Cullet containing copper or any of the copper oxides also must be kept from the batch as it cannot be controlled and tends to deepen the color. Tank and furnace conditions are of great importance in making good ruby glass. A soft reducing flame must be used when melting in a day or continuous tank. When the glass is made in a closed pot, the stoppers should be kept sealed until the chemical reaction has almost ceased. If air or oxygen is allowed to enter the pot, the condition changes from reducing to oxidizing and results in poor color. If any air is allowed to enter the pot, a strong reducing agent should be used to drive off the gases. Submit equipment definitions online at www.ceramicindustry.com/materialshandbook

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SILICA, FUMED

flint and used in the pottery, enamel and terra cotta industries. It is used as fused quartz and crystalline quartz in the electronic ceramic industry. Glass Sands: For the purpose of glass manufacture, however, it is necessary that quartz be not only an essential constituent of the silica rock, but it must be practically the only constituent present. Sand deposits and sandstones are found in nature that analyze >99% silica. In the present-day manufacture of glass, nearly pure quartz sands are used almost exclusively as the source of silica, which is the major constituent of all common varieties of glass. Ordinary soda-lime glasses, such as bottle, common tableware, plate and window glasses, contain 65-75% silica. Glass sands occur in nature either in the form of loose, unconsolidated sediments or in deposits in which the individual grains have been bound together by some cementing agent so as to form sandstone. While deposits of sand and sandstones are abundantly distributed, deposits that are sufficiently free of other constituents, particularly iron oxide, are comparatively rare. West Virginia, Illinois, Pennsylvania, New Jersey and Missouri supply 80-90% of all glass sand used in the U.S. In Pennsylvania and West Virginia, the bulk of the glass sand produced is derived from Oriskany quartzite. For almost a century, the most important source of silica for the production of glass has been the Oriskany quartzite deposits in the eastern United States. In Illinois and Missouri, practically all of the glass sand is derived from the St. Peter sandstone. In New Jersey, glass sands occur as horizontal beds of unconsolidated sand, sometimes 90 ft thick and capped by 1-15 ft of gravel, sand and loam. Silica of the purity required for the manufacture of glass and ceramics is found in south-central Oklahoma in the Oil Creek quartzite of the Ordovician Age. Located in the heart of the Southwest, this deposit is fast becoming a major source for Western glass and ceramic manufacturers. In California, sand is mined from sedimentary sandstone formations of early tertiary age (namely Paleocene deposits south of Mission Viejo, in the Trabuco Canyon area of Orange County) and Eocene deposits near Ione in Amador County and Oceanside in San Diego County. These deposits are essentially feldspathic sands containing clays and heavy minerals. In most cases, glass sand on the West Coast is recovered only after beneficiation. Oriskany and St. Peter sandstones remain the two major sources of glass sand in the United States. Uniformity in grain size is perhaps of more importance in a glass sand than the actual size of the grains themselves. If the sand grains are too fine, the first reaction will take place so rapidly that the large volumes of carbon dioxide liberated will cause the batch to foam badly and, in case of a tank furnace, excessive amounts of material will be carried into the checkers of the regenerators and into the flues. Too fine a sand also may be responsible for the formation of a fine, persistent seed in the glass. The coarser the sand used, the greater is the tendency for the formation of batch scum. A sand containing only a few percent of coarse grains is more likely to cause scum, stones and cords than a sand in which all the grains are uniformly coarse. If sand grains are uniform in size, the attack on them will be approximately uniform and consequently they will decrease in size at a uniform rate. On the other hand, if the sand is composed of a few percent of large grains and the remainder relatively small grains, the solution of the small grains will be completed before the large grains have decreased but very little in size. The finer portions of a glass sand are apt to contain a large part of the undesirable iron-bearing minerals of the sand, such as magnetite and ilmenite. If the sand

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Materials Handbook

grains are coated with small amounts of limonite or hematite, the finer sand, on account of its greater surface area in proportion to its weight, will contain the highest percentage of iron. The silica (actually ground silica) used in the pottery industry is called flint. The addition of flint affects warpage very little. Bleininger and Stull found that porosity decreased more in high flint bodies than in high clay bodies. In ceramic bodies, potters’ flint or pulverized quartz or sand is the constituent which reduces drying and burning shrinkage and assists promotion of refractoriness. Flint has an important bearing on the resistance of bodies to thermal and mechanical shock, because of the volume changes which accompany crystal transformation. In the unburned body, it lowers plasticity and workability, lowers shrinkage and hastens drying. A coarse crystalline form of quartz, called macrocrystalline quartz, is more often used for potters’ flint than the cryptocrystalline form. Cryptocrystalline flint will show more cristobalite development under heat treatment than will quartz flint. This property has an important bearing on thermal shock resistance of whiteware bodies, allowing more resistant bodies to be made using quartz flint. Impurities in the flint and the fineness to which it is ground have a decided effect on the behavior of the body; this effect is probably of more commercial importance than that caused by the type of flint used. The maturing temperature of a body is now lowered materially by the use of cryptocrystalline flint, but overfiring will take place more rapidly than in bodies where quartz flint is used. Purdy and Potts found that with any mixture of flint and feldspar, or even when added at the expense of flint, clay slightly increases rather than decreases the coefficient of expansion. Up to 45% flint added to any constant clay-tofeldspar ratio slightly decreases the coefficient of expansion and tends to reduce crazing. Silica is used in all glazes as the chief, and often the only, acid radical (RO2 group). It may be adjusted to regulate the melting temperature of the glaze. In common glazes, the ratio of silica to bases (RO group) is never less than 1:1 nor more than 3:1. By varying the relative proportions of the RO group and balancing the group against any desired silica content, the maturing temperature of a glaze may be quite closely controlled. In other words, the fusibility of the glazes used in the presence of equal proportions of fluxes depends on their relative silica contents. In porcelain enamels, it may be taken as a general rule that, other things remaining constant, the higher the percentage of silica, the higher will be the melting point of the enamel and the greater its acid resistance. Silica has a low coefficient of expansion and increasing it in an enamel lowers the coefficient of expansion of that enamel. One method of regulating an enamel coating is to increase the silica content when the enamel is inclined to split off in cooling. Silica in the form of flint or quartz is used in both ground-coat and cover-coat enamels, and it has the same effect in either type. The temperature required for melting an enamel is materially affected by the fineness of the silica. Cryolite, antimony and tin oxide give their maximum value as opacifiers with minimum heat treatment in the smelter. The form and fineness of the silica should, therefore, be carefully watched and allowed for in compounding the batch. All forms of silica may be used with good results, but experience has shown that, in the same enamel, a smaller quantity of sand than of powdered quartz is necessary. Similarly, less sand than flint should be used, but the difference in this case is less than in the former. High SiO2 tends to harden the enamel. The lower limit established in the usual run of enamels is 1.1 equivalents.

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In the manufacture of semiconductors, monolithic circuits and integrated circuits for the electronics industry, the use of fused quartz is widespread for plumbing and diffusion furnace muffles. The need to prevent product contamination makes this choice mandatory. SILICA SUPPLIERS

U.S. SILICA CO. P.O. Box 187 Berkeley Springs, WV 25411 (304) 258-2500; (800) 345-6170 Fax: (304) 258-8295 Email: [email protected] Website: www.u-s-silica.com

UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected] SILICA, COLLOIDAL. Colloidal silica is an aqueous dispersion of discrete particles of amorphous silica. The silica particles have a negative surface charge which causes the particles to repel one another, resulting in a stable silica sol. Silica sols find numerous uses because they dry irreversibly to insoluble silica. They are useful as binders and rigidizers for inorganic fibers and powders. SILICA, COLLOIDAL SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com WESBOND CORP. 1135 E. 7th St. Wilmington, DE 19801 (302) 655-7917 Fax: (302) 656-7885 Website: www.wesbond.com SILICA, FUMED. SiO2. M.p. 1550-1570C. Sp.gr. 2.2-2.3 g/ cm3. Bulk density 150-700 kg/m3. An amorphous silicon dioxide (silica), consisting of sub-micron spherical primary particles and agglomerates of these. The material is highly reactive in cementitious and ceramic bond systems. Silica fume is a key ingredient in advanced low, ultra-low and cement-free castables. It is highly reactive during sintering, and leads to improved ceramic bonding (mullite, forsterite, etc.), both in high alumina and magnesite based products. It is also used in mortars, gunning mixes and other unshaped materials. (See MICROSILICA.)

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SILICA, FUMED

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SILICATE

SILICA, FUSED SUPPLIERS CONTINUED SILICA, FUMED SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net Z-TECH LLC 8 Dow Rd. Bow, NH 03304 (603) 228-1305 Fax: (603) 228-5234 Email: [email protected] Website: www.z-techzirconia.com SILICA, FUSED. (Quartz.) The desired property of this material is its low coefficient of thermal expansion. It is primarily used in refractories for kiln and furnace walls, and as a shell material for molds in investment casting. Used in the electronics industry as an inert, low expansion filler for epoxy resins. Each chip or microcircuit is packaged in a blend of fused silica and epoxy for protection. One additional use is windows for spacecraft and other high temperature applications. Successful refractories have been made by adding fused silica to the body. Quartz in itself, after it is fused, has a very low coefficient of expansion and actually assists in bringing out a good heat resistant type of body. A danger of recrystallization of quartz is possible if reheated too high and too many times which, of course, would destroy the low coefficient of expansion. Silica refractories are made from gannister and quartz rock. These refractories are very commonly used in roofs of glass tanks and open hearth furnaces. The rock is ground to a specified size range. The silica then is mixed with a binder, sometimes even molasses, and then shaped into form either by dry pressing or by a drop press. Silica is fired to ~2700°F for the final formation. Lime sometimes is used as the binder and also acts as a flux. Two types of silica refractories are made: (1) the common variety and (2) a very low-alumina variety. Alumina up to ~4% acts as a flux, lowering the service temperature of the silica brick.

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com SILICA GELS, AMORPHOUS. Amorphous silica gels are composed of fine-particle silica manufactured by the gel process. They have high purity and are available in various particle size ranges, with high and low internal porosity, precisely controlled pore size, variable surface areas and surface treatment modifications. Silica gels can be used in powder coatings to improve freeflow and dispersion by absorption/adsorption of moisture, which can cause caking and agglomeration. The silica also coats the larger powder particles, physically separating them to prevent packing or fusion due to compression. Amorphous silica gels can also be used as rheology modifiers because they promote thickening and flow control in liquid systems by adsorbing the liquid onto the silica surface absorbing it into the pores. Some thixotropic effects are imparted by hydrogen bonding between silanol groups on aggregate surfaces. SILICA, HIGH-PURITY. (High purity quartz.) High purity silica is distinguished by its purely crystalline (unfused) structure,

by contamination level measured in parts per million (ppm), and by an overall purity greater than 99.99%. It is used in specialty applications such as ultrapure furnaceware, crucibles, unusual glasses, fused quartz, halogen lamp envelopes and other applications where even small amounts of contamination degrade or compromise performance. SILICA, HIGH-PURITY SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com SILICATE. A compound composed of silicon, oxygen and one or more metals.

SILICA, FUSED SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

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SILICATE OF SODA

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SILICON CARBIDE

SILICATE OF SODA. Na2O-SiO2. Used as a deflocculant in ceramic bodies and as a major component in air- and heatcuring cements. SILICON AND COMPOUNDS OF. Si. At. wt. 28.06; m.p. 1430°C; sp. gr. 2.42. Second most abundant element but occurs only in compounds, never in the free state. It is a gray-white, brittle, metallic-appearing element, not readily attacked by acids except by a mixture of HF and HNO3. Soluble in hot NaOH or KOH. Prepared in the pure crystalline form by reduction of fractionally distilled SiCl4. By far the largest use of silicon is as compounds in the ceramic industry. It also is employed as an alloying element in ferrous metals, and is the basis of the family of chemicals known as silicones. (See specific compound listings, as well as SILICA, SILICATES, SILICONES, etc.) An important application of silicon is in the electronics industry where it has been widely employed in the manufacture of crystal rectifiers and integrated circuits. Sufficiently pure silicon has been produced by carefully controlled zone refining and crystal growth to make possible its use as transistors. Since the energy gap in silicon is 1.1 eV, compared with 0.75 eV for germanium, silicon transistors may be operated at higher temperatures and power levels than those made of germanium. Silicon is purified by converting it to a silicon compound that can be more easily purified by distillation than in its original state, and then converting that silicon compound back into pure silicon. Trichlorosilane is the silicon compound most commonly used as the intermediate, although silicon tetrachloride and silane are also used. When these gases are blown over silicon at high temperature, they decompose to high-purity silicon.

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SILICON CARBIDE. SiC. Mol. wt. 40.07; sp. gr. 3.22. Commercial SiC is produced in an electric furnace from a mixture of coke and silica sand (>99.4% SiO2), which sometimes also contains sawdust and salt or another binder. An electric current passed between permanent electrodes located at both ends of the furnace, and through a graphite core, produces a temperature higher than 2200°C, at which point crystals of silicon carbide form from the sand-coke charge. Beta-SiC (cubic) forms at 14001800°C and alpha-SiC (hexagonal) forms at temperatures >1800°C. If used, the sawdust burns out, keeping the mass porous, and the salt assists in the removal of impurities through a formation of volatile chlorides. A furnace run takes ~36 hr. Another method used to form SiC pieces is by vapor deposition of silicon onto a heated graphite or carbon surface. SiC has been found in nature in meteoric iron and in diamond mineral assemblages in South Africa and the former USSR. SiC is extremely hard (Mohs 9.1 or 2500 Knoop); has high thermal conductivity (100 W/mK); and high strength at elevated temperatures (at 1000°C, SiC is 7.5 times stronger than Al2O3). SiC has a modulus of elasticity of 410 GPa, with no significant decrease in strength up to 1600°C, and it does not melt at normal pressures but instead dissociates at >2815.5°C. The material is a semiconductor, exhibiting 0.1 Ohm-cm resistance in porous recrystallized form, and is capable of rectification and electroluminescence. SiC oxidizes very slowly in air, and is serviceable to 2800-3000°F for many uses. It is not attacked by acids, but reacts readily with fused caustic, halogens and certain metal oxides at high temperatures. SiC’s CTE is 5.2 x 10-6/C (25-1500°C); Weibull modulus is 10; Poisson’s ratio is 0.16.

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Materials Handbook

Three main types are produced commercially. Green SiC is an entirely new batch composition made from a sand and coke mixture, and is the highest purity of the three. Green is typically used for heating elements. Black SiC contains some free silicon and carbon and is less pure. A common use is as bonded SiC refractories. The third grade is metallurgical SiC, and is not very pure. It typically is used as a steel additive. Typical green and black SiC compositions (in %) are compared in the table below.

Silicon carbide is manufactured in many complex bonded shapes, which are utilized for super-refractory purposes such as setter tile and kiln furniture, muffles, retorts and condensors, skid rails, hot cyclone liners, rocket nozzles and combustion chambers, and mechanical shaft seals. It is also used for erosion- and corrosion-resistant uses, such as check valves, orifices, slag blocks, aluminum die-casting machine parts and sludge burner orifices. Electrical uses of SiC include lightning arrestors, heating elements and nonlinear resistors. Silicon carbide materials also offer superior friction and wear characteristics when used in mechanical seals and pump bearings. High hardness, strength, and thermal conductivity make them excellent mating components for all types of high-performance applications. There are different families of materials, including reaction-bonded materials, which contain free silicon metal; sintered materials, which offer superior chemical resistance; chemical vapor deposited materials, which offer enhanced tribological properties; and composites of silicon carbide, which can contain graphite (for lubricity) and/or porosity (to improve marginal lubrication situations). These materials are typically run against carbongraphite materials or against themselves, depending on the application requirements. Silicon carbide refractories are classified on the basis of the bonds used. Associated-type bonds are oxide or silica, clay, silicon oxynitride and silicon nitride, as well as selfbonded. The dense materials contain 85-99% SiC; the clay-bonded contain 75-80% SiC; and the semisilicon carbides are still lower in SiC content. Properties vary according to the types and amounts of bond used. Generally speaking, SiC refractories exhibit properties that warrant their use in kiln furniture applications, structural members, chemical and municipal incinerators, coal handling equipment, recuperator tubes, muffles, retorts, crucibles and pyrometer protection tubes. Added to plastic fireclays, silicon carbide imparts high thermal emissivity and conductivity to the refractory and extends the useful application of this material. Silicon carbide also finds application as refractory cements for laying SiC brick or shapes, ramming or patching linings, and washes. These cements or mortars are sized for each specific application. Bonds generally of a phosphate- or clay-type impart a thermal working range to the particular cement and mature at predetermined temperatures. In addition, SiC is used in the manufacture of grinding wheels and coated abrasives. Large tonnages are used in cutting granite with wire saws and as a metallurgical addiSupplier listings indicate paid advertising.

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SILICON CARBIDE

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SILICON NITRIDE

SILICON CARBIDE SUPPLIERS CONTINUED tive in the foundry and steel industries. About 700,000 tons are produced per year, of which 33% is used as a metallurgical additive and 50% is used in the abrasives industry. The remainder is used in the refractory and structural ceramic industries. As an abrasive, silicon carbide is best used on either very hard materials such as cemented carbide, granite and glass, or on soft materials such as wood, leather, plastics, rubber, etc. The specific electrical resistivity of SiC single crystals depends on purity. Values at room temperature range from 2.1-0.4 Ohm-cm. Single crystals formed by traveling solvent method have the higher purity needed for rectifier applications in the 10 A range and operating temperatures up to 500°C. Low power injection lasers are possible with SiC. Electronic applications include thermistors, varistors and attenuator material for microwave devices. SILICON CARBIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

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SILICON METAL POWDER SUPPLIERS

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com SILICON METAL POWDERS. Silicon metal powders are used in the chemical industry, primarily to produce silicones. High-purity forms are also used for making computer chips and other electronic components. (See SILICONES and MICROSILICA.)

CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com

BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com SILICON NITRIDE. Si3N4. Mol. wt. 140.28; sp. gr. 3.19. Dissociates in air at 1800°C and at 1850°C under 1 atm N2. Two crystal structures: alpha (1400°C) and beta (14001800°C), both hexagonal. Hardness approximately 2200 on Knoop K100 scale. Excellent corrosion and oxidation resistance over a wide temperature range. Typical applications: molten-metal-contacting parts, wear surfaces, special electrical insulator components and metal forming dies. Under evaluation as gas turbine and heat engine components as well as antifriction bearing members. Pure silicon nitride powders are produced by several processes, including direct nitridation of silicon, carbothermal reduction—C + SiO2 + N2 yields Si3N4 (gas atmosphere)—and chemical vapor deposition—3SiH4 + 4NH3 yields Si 3N 4 + 12H 2. Reacting SiO 2 with ammonia, or silanes with ammonia will also produce silicon nitride powders. It is found that the highest purity powders come from gas-phase reactions. Polymer pyrolysis at 6001200°C using trimethylsilane will produce high-purity powder. Example: 90% alpha-phase Si3N4 with a mean particle size of 0.7-10 +m. (Powders having other levels of alpha phase also can exhibit a similar particle size.)

ESK CERAMICS GMBH & CO. KG Max-Schaidhauf-Str. 25 Kempten 87437 Germany (49) 831-56180 Fax: (49) 831-5618345 Email: [email protected] Website: www.esk.com

SAINT-GOBAIN CERAMICS, STRUCTURAL CERAMICS, HEXOLOY® PRODUCTS 23 Acheson Dr. Niagara Falls, NY 14303-1597 (716) 278-6233 Fax: (716) 278-2373 Email: [email protected] Website: www.hexoloy.com SUPERIOR GRAPHITE CO., INDUSTRIAL PRODUCTS 10 S. Riverside Plaza Chicago, IL 60606 (312) 559-2999; (630) 841-0099 Fax: (312) 559-9064 Email: [email protected] Website: www.superiorgraphite.com

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Materials Handbook SILICON NITRIDE SUPPLIERS CONTINUED

Pure Si3N4 powders are very difficult to sinter, and in pure form cannot be formed into shapes nor densified to a pore-free state, since atomic mobility in the material is low and Si 3N 4 vaporizes at very high temperatures. Descriptions of two main types of silicon nitride follow: Sinterable/Hot Pressed/Hot Isostatically Pressed Silicon Nitrides. (SSN, HPSN and HIPSN, respectively.) Used mainly in higher performance applications. Powdered additives, known as sintering aids, are blended with the pure Si3N4 powder and allow densification to proceed via the liquid state. Pore-free bodies can be so produced by sintering or hot pressing. Of course, the properties of the material and dense pieces are dependent on the chemical nature of the sintering aid(s) employed. Sinterable silicon nitrides are a more recent innovation, and allow more flexibility in shape fabrication than does HPSN. Highly complex shapes can be die pressed or isostatically pressed. Densification can be performed by either sintering or hot isostatic pressing (HIP). Properties of the dense piece are dependent on the additives, but in general the strength below 1400°C, as well as oxidation resistance of HPSN and SSN, far exceed those properties for RBSN. For example, a commercially available HPSN has a density of 3.2 g/cm3, CTE of 3.2 x 10-6/C, thermal conductivity of 32 W/mK, modulus of elasticity of 46 x 106 psi, and MOR of 143,000 psi at room temperature and 60,000 psi at 1375°C (type NC). Hardness is 2200 (Knoop K100). HPSN has typical values of: specific heat, 0.17 cal/gC; toughness, 6.6 MPam; and mean Weibull modulus, 12. More common today is Reaction Bonded Silicon Nitride (RBSN). Silicon powder is pressed, extruded or cast into shape then carefully nitrided in a N 2 atmosphere at 1100-1400°C, so as to prevent an exothermic reaction that might melt the pure silicon. The properties of RBSN are usually lower than those of HPSN or SSN, due mainly to the fact that bodies fabricated in this manner only reach 85% of the theoretical density of silicon nitride and no secondary phase between grains is present. Sp. gr. is 2.5 g/cm3; hardness is 9001000 kg/mm2 (VHN, 0.5 kg load); Charpy impact energy is 2.0 ft-lbf/in.2; tensile strength is 145 MPa; and compressive strength is 1000 MPa. The thermal conductivity of RBSN at room temperature is 8-12 W/mK; CTE is 3.2 x 10-6/C; Poisson’s ratio is 0.27; and Weibull modulus is 10-15. Commercial RBSN of type NC350 has a density of 2.4 g/cm3 and an MOR of 40,000 psi at room temperature and 50,000 psi at 1375°C.

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CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com

ESK CERAMICS GMBH & CO. KG Max-Schaidhauf-Str. 25 Kempten 87437 Germany (49) 831-56180 Fax: (49) 831-5618345 Email: [email protected] Website: www.esk.com

SAINT-GOBAIN CERAMICS, STRUCTURAL CERAMICS, HEXOLOY® PRODUCTS 23 Acheson Dr. Niagara Falls, NY 14303-1597 (716) 278-6233 Fax: (716) 278-2373 Email: [email protected] Website: www.hexoloy.com

H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

ABCR GMBH & CO. KG Im Schlehert 10 Karlsruhe 76187 Germany +49 (0)721 95061 11 Fax: +49 (0)721 95061 - 71 Email: [email protected] Website: www.abcr.de

SILICON OXYNITRIDE SUPPLIERS

SILICON, POLYCRYSTALLINE. Polycrystalline silicon, or polysilicon, poly-Si or simply poly (in context), is a material consisting of multiple small silicon crystals that has long been used as the conducting gate material in metal-oxide semiconductor field-effect transistor (MOSFET) and complementary metal oxide semiconductor (CMOS) processing technologies. For these technologies, it is deposited using low-pressure chemical vapor deposition (LPCVD) reactors at high temperatures, and is usually heavily N or P-doped. Intrinsic and doped polysilicon is being used in largearea electronics as the active and/or doped layers in thin-film transistors. Although it can be deposited by LPCVD, plasma-enhanced chemical vapor deposition (PECVD) or solid-phase crystallization (SPC) of amorphous silicon in certain processing regimes, these processes still require relatively high temperatures of at least 300°C. These temperatures make deposition of polysilicon possible for glass substrates, but not for plastic substrates. The drive to deposit polycrystalline silicon on plastic substrates is powered by the desire to be able to manufacture digital displays on flexible screens. Therefore, a relatively new technique called laser crystallization has been devised to crystallize a precursor amorphous silicon (a-Si) material on a plastic substrate without melting or damaging the plastic. The main advantage of polysilicon over a-Si is that the mobility of the charge carriers can be orders of magnitude larger, and the material also shows greater stability under electric field and light-induced stress. This allows more complex, high-speed circuitry to be created on the glass substrate along with the a-Si devices, which are still needed for their low-leakage characteristics. Hybrid processing is the method by which polysilicon and a-Si devices are used in the same process. A complete polysilicon active layer process is also used in cases where a small pixel size is required, such as in projection displays. Polysilicon is a key component for integrated circuit and central processing unit manufacturers, and it is also a key component of solar panel construction. Source: Wikipedia, http://en.wikipedia.org.

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com SILICON OXYNITRIDE. Si2N2O. Silicon oxynitride can be synthesized from mixtures of silicon nitride and silica in conjunction with densification additives. With Al2O3 present,

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Source: Engineered Materials Handbook, Vol. 4, Ceramics and Glasses, ASM International, Materials Park, OH 44073-0002, p. 819.

ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

SILICON NITRIDE SUPPLIERS

ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected]

some limited solubility occurs. Pressureless sintering and pressure-assisted processes may be employed. Mechanical properties of silicon oxynitride are inferior to those of silicon nitride, but the material may have potential in certain thermomechanical applications because of its lower Young’s modulus and slightly higher thermal expansion coefficient, which make it more suitable for bonding to metals.

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SILICONES. Silicones can be described as a marriage between sand and oil, the original raw materials. Despite extensive refinement, the final silicone products actually exhibit an amazing correlation of properties to these materials. Silicones combine the general properties of petroleum based compounds with the heat and chemical stability of silica. The name silicone refers to a polysiloxane, the structure of which has alternating silicon and oxygen atoms (Si-OSi-O). The structure is comparable to that of a carbon chain and, as in organic chemistry, the length of the chain Supplier listings indicate paid advertising.

2012 Edition

(size of the molecule) and the degree of crosslinking determine the form of the silicone. The outstanding characteristic of silicones is their small change of properties over a wide temperature range (-70 to +250°C). Other characteristics that are important in the wide variety of applications of silicones are water repellency, good dielectric properties, low surface tension, nonstick properties and lack of toxicity. The high water repellency characteristic of silicones is used extensively in the ceramic industry. Above-grade siliceous walls are made water repellent for up to ten years with one coating of silicone resin. Highways, asbestos shingles, rock wool insulation (to prevent settling), and fiber glass flotation mats—the filler for life jackets—can all be effectively treated with silicones. A cement based paint containing silicones is used to waterproof masonry structures that are subjected to considerable heads of water. The abhorrence for water and good dielectric properties of silicones are employed in surface treatments for electrical insulation. The coating prevents the formation of a continuous film of water on the dielectric and effectively stops surface leakage. For nonporous ceramic, the coating is a baked-on fluid; for porous ceramic, a resin; and for ceramic insulation for high power lines, a grease. Silicones are used as release agents on plywood forms for concrete, in glass molds, and on specialty brick molds. They provide slip for glass mold delivery equipment, are used as an antiseize agent on bottles and are applied to the inside of glass containers to ensure complete drainage of liquid. Where high temperatures are encountered, glass fiber laminates use silicones as the bonding agents. Totally enclosed motors, which are found where there is high dust concentration, solve their heat problem with Class H (silicone) insulation. Silicone-vehicle paints are used on furnaces and stacks. Special high temperature flat glass laminates, primarily for airplanes, have an interlayer of silicone. This particular material is rubber-like when fully cured, is not brittle at temperatures as low as -100°F and is stable at 350°F. SILICONE SUPPLIERS GELEST INC. 11 E. Steel Rd. Morrisville, PA 19067 (215) 547-1015 Fax: (215) 547-2484 Email: [email protected] Website: www.gelest.com SILVER. Ag. At. wt. 107.88; sp. gr. 10.5. Silver is a little harder than gold and is excelled only by that metal in malleability and ductility. It is mined in Idaho, Utah, Colorado, Arizona, Montana, Mexico, Canada, Japan and South America. Metallic silver is used in the decoration of pottery and glassware. There are several preparations: precipitated or powdered silver, fluxed silver, paste silver and white gold paste. Precipitated or powdered silver is a preparation analogous in use and properties to brown gold, although not usually so finely divided. While it changes rather easily in color due to oxidation and tarnish, its use may be extended by waxing or lacquering the fired surface. As a fired base for the electrolytic deposition of additional silver, it finds most use in glass decoration, although silver oxide or silver paste is used for the same purpose. Practically all precipitated silver is fluxed. Paste silver differs from gold pastes only in that the gold is replaced by silver; in white gold paste, both powdered silver and powdered gold are present. The addition of gold to the silver changes the color to a somewhat greenish hue and at the same time lessens the tarnishing action in proportion

SILICONES

to the amount of gold added. Silver preparations may be fired at lower temperatures than gold pastes. The resultant decoration must be burnished to bring out the characteristic silver color. No liquid bright silver exists. In general, a more satisfactory silver effect is produced by platinum or palladium. Advanced ceramic applications: Silver is unsurpassed as a conductor of heat and electricity. Silver is used in conductive coatings for capacitors, printed wiring and printed circuits on titanites, glass bonded mica, steatite, alumina, porcelain, glass and other ceramic bodies. These coatings also are used to metallize ceramic parts to serve as hermetically sealed enclosures, becoming integral sections of coils, transformers, semiconductors, and monolithic and integrated circuits. Two types of conductive coatings can be used on ceramic parts: those that are fired-on and those that are baked-on or air dried. The fired-on type contains, in addition to silver powder, a finely divided low melting glass powder; temporary organic binder; and liquid solvents in formulations having direct soldering properties and others suitable for electroplating, both having excellent adhesion and electrical conductivity. The baked-on and air-dry types contain, in addition to silver powder, a permanent organic binder and liquid solvents. These preparations have somewhat less adhesion, electrical conductivity and solderability than the fired-on type, but can be electroplated if desired. The air-dry type is used when it is not desirable to subject the base material to elevated firing temperatures. Any of the above silver compositions are available in a variety of vehicles suitable for application by squeegee, brushing, dipping, spraying, bonding wheel, roller coating, etc. Firing temperatures for direct-solder silver preparations range from 1250-1450°F. Silver compositions to be copper plated are fired at 1200-1250°F. The firing cycle used with these temperatures will vary from 10 min to 6 hr, depending upon the time required to equalize the temperature of the furnace charge. A 62Sn-36Pb-2Ag solder is generally used with the direct-solder silver compositions. It is recommended that this solder be used at a temperature of 415-425°F. Soldering to the plated silver coating is less critical and 50Sn-50Pb or 40Sn-60Pb, as well as other soft solders, are being used with good results. The air-dry silver compositions will, as the designation implies, air dry at room temperature in approximately 16 hr. This drying time can be shortened by subjecting the coating to temperatures of 140-200°F for 10-30 min. The baked-on preparations must be cured at a minimum temperature of 300°F for 5-16 hr. The time may be shortened to 1 hr by raising the temperature to 575°F. The same soft solders and techniques as recommended for the fired-on coatings may be used for the electroplated air-dry and baked-on preparations. It is extremely difficult to solder to air-dry or baked-on coatings without first electroplating. The surface conductivity of the fired silver coating is far better than that of the air-dry or baked-on coating. Fired coatings have a surface electrical square resistance of approximately 0.01 ohm while the surface electrical square resistance of air-dry or baked-on coatings is about 1 ohm. SILVER CARBONATE. Ag2CO3. Mol. wt. 276; sp. gr. 6.1; m.p. 230°C; decomposes at 270°C; slightly soluble. Silver carbonate is used to produce iridescent stains or sheens on glazes. This work should be done at low temperature, preferably around 300-700°C. One silver luster is made by adding up to 2% silver carbonate or silver oxide to a transparent colorless lead glaze and firing in a slightly reducing atmosphere. Silver carbonate sometimes replaces silver chloride in the preparation of cantharigin luster, and it may replace silver nitrate in coloring glass yellow.

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SODIUM METASILICATE

SILVER CHLORIDE. AgCl. Mol. wt. 143; sp. gr. 5.6; m.p. 455°C; decomposes at 1550°C; is soluble in ammonium hydroxide and strong sulfuric acid and slightly soluble in water. It is derived by heating a silver nitrate solution with hydrochloric acid or a chloride salt in the dark. A common impurity is silver nitrate. Silver chloride is used in the preparation of yellow glazes, purple of Cassius and silver lusters. A yellowish-silver luster is obtained by mixing silver chloride with three times its weight of clay and ochre and sufficient water to form a paste. Cantharigin luster is a varied and brilliant metallic coloring that is obtained by a mixture of lead borate, a little bismuth oxide and silver chloride; a silver carbonate can be used in place of the chloride. This luster should be fired in a muffle furnace at about 700°C and in a fairly reducing atmosphere. Other silver lusters are made simply by mixing silverchloride or nitrate with fat oil, lavender oil or other ethereal oil, or with nitrobenzene or honey. Such lusters have a greenish tint with a hint of gold. SILVER NITRATE. AgNO3. Mol. wt. 170; sp. gr. 4.3; m.p. 212°C; decomposes at 444°C; soluble, corrosive and poisonous. It is prepared by the action of nitric acid on metallic silver. Silver nitrate is the most convenient method of introducing silver into a glass; a solution of the compound is poured over the batch. A very low concentration of silver produces a colorless glass which, upon reheating, can be struck to a yellow. This yellow, however, is inclined to be opalescent or even opaque, and hence this colorant does not have any considerable applications. Several lusters are made with silver nitrate, notably the one prepared by mixing solutions of silver nitrate and resin soap to produce a silver resinate, which is compounded with lavender oil. Silver nitrate lusters and gernally yellowish with little metallic gloss. SILVER OXIDE. Ag2O. Mol. wt. 232; sp. gr. 7.1-7.5; decomposes when heated above 300°C; soluble in acids and ammonium hydroxide and very slightly soluble in water. It is prepared by the interaction of silver nitrate and alkali hydroxide. Silver oxide is used as a coloring agent in glazes. It usually produces a yellow color, but in the presence of lime or zinc compounds the color is brownish, and with boric oxide the glaze is gray. In a reducing atmosphere a metallic luster is produced. In the ceramic field other silver compounds are usually preferable to the oxide. SMALT. (See COBALT OXIDE.) SODIUM BICARBONATE. NaHCO3. Used as a deflocculating agent, as a body wash to improve body-glaze reactions, and as a metal cleaning agent in solutions. SODIUM BICARBONATE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com SODIUM METASILICATE. A solid white granular salt with the chemical formula: Na2SiO3-5H2O. It melts in its own water of crystallization at 72°C, above which it is miscible with water in all proportions. It is strongly alkaline. Also available in the anhydrous form, Na2SiO3. Sodium metasilicate is used in amounts of 10-40% in practically all commercial preparations for cleaning drawing compounds from enameling stock.

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SODIUM METASILICATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com Z-TECH LLC 8 Dow Rd. Bow, NH 03304 (603) 228-1305 Fax: (603) 228-5234 Email: [email protected] Website: www.z-techzirconia.com SODIUM NITRATE. (Soda niter.) NaNO3. Mol. wt. 85; sp. gr. 2.3; m.p. 208°C; decomposes at 380°C; soluble. Derived from Chilean caliche deposits or atmospheric nitrogen. Sodium nitrate is used in enamel frits in quantities of 2-8%. It is highly important that sufficient nitrate be present in enamels to prevent reduction of any easily reducible compounds in the batch, especially lead or antimony compounds. The color of the resulting enamel is materially affected by slight reduction, which may be caused by smoky flame or by carbonaceous compounds incorporated in the batch. It is of special importance that enamels containing antimony oxide have sufficient oxidizing agents. Reduction of such an enamel not only causes the antimony to go into solution, thereby losing its opacifying power, but also destroys the color of the enamel. The function of sodium nitrate in glass is to oxidize organic matter which may contaminate batch materials, to prevent reduction of some of the batch constituents, to help maintain colors and to speed up the melt. It is the lowest melting of all glassmaking materials. Common applications of sodium nitrate are to ensure the pink color of manganese oxide and to prevent reductions of lead in potash lead glasses. SODIUM NITRATE SUPPLIERS SQM NORTH AMERICA CORP., INDUSTRIAL 2727 Paces Ferry Rd. S.E. Ste. 2-1425 Atlanta, GA 30339-6160 (770) 916-9426 Fax: (770) 916-9401 Email: [email protected] Website: www.sqm.com SODIUM PHOSPHATE. Na2HPO4-12H2O. Mol. wt. 358.21; sp. gr. 1.52; m.p. 346°C; soluble in water. Sodium phosphate has been recently added to glass batches producing an opal glass of unusual properties. Three other forms of the phosphate are available—monobasic, tribasic and pyrophosphate. The last is most adaptable since it melts at 970°C in the anhydrous form. It is derived by the fusion of disodium phosphate. In the tetra form (Na4P2O7), it is used as a deflocculant in glazes and enamels, and in the purification of clays. It is also used as a means of removing iron from clays by washing. It is an efficient water conditioning agent and as such may be used when the effect of hard water produces undesirable results. As a source of P2O5 it has been suggested as a raw material for the manufacture of opal glasses and enamels. The fact that it contains soda instead of calcia is of some advantage in certain types of work. In the glass industry the major uses of borax do not permit substitution of sodium tetraphosphate, but in some of the smaller applications it has found a place.

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SODIUM PHOSPHATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com SODIUM SELENITE. (See SELENIUM.) SODIUM SILICATE. Na2O-xSiO2. Sodium silicates are commonly made by melting sand and soda ash in a reverberatory furnace. Various proportions of the two ingredients are used and widely divergent characteristics result. The most alkaline liquid silicate made by this furnace process has a ratio of 1Na2O:1.6 SiO2, and the most siliceous liquid grade has a ratio of 1 Na2O:3.75 SiO2. There are more alkaline sodium silicates made that are detergents and are known as metasilicate (Na2O-SiO2), sesquisilicate (3Na2O-2SiO2-(11H-V2O) and orthosilicate (2Na2O-SiO2). They are of interest to the ceramic manufacturer because they are effective for cleaning metal prior to enameling. The melted sand and soda ash coming from the furnace may be put immediately into solution. The most siliceous grade cannot be concentrated beyond about 32% total solids without going to a gel, but the most alkaline liquid can be concentrated to about 61% total solids and still remain fluid. Instead of forming solution, the melt also may be cooled to a glass that can only be dissolved in high pressure steam. The glass also may be crushed to a fine powder useful as an ingredient in acid-resistant enamels discussed elsewhere under this heading. Those silicates high in silica are more potent deflocculating agents for a given Na2O content than the more alkaline sodium compounds, such as sodium hydroxide or sodium carbonate. In general, 0.2-0.5% of sodium carbonate and sodium silicate are used. Sodium silicate as a deflocculant eases the drying of a body in that there is less strain in the ware due to the absence of much water. The ware dries very hard and tough which decreases loss in the green state. If one form of sodium silicate added to a clay in amounts of <2% based on a 40% solution can cause differences of more than 100% in the dry strength or the fired strength of clays, it is a matter of concern to know whether the form arbitrarily chosen for the study was in fact the most suitable. Sodium silicate glass, anhydrous and crushed to pass 20 mesh, ratio 1:3.2, has found some use as a raw material for enamels. It lowers the time required to bring about complete solution of the silica in the batch. Batches containing sodium silicate instead of quartz for the silica introductory material, show no free silica in the enamel. However, as the silicate is more expensive than the ingredients it replaces, it has only been used commercially in enamels hard to make, or in which special effects are desired. It has been found particularly good for use in acid-resisting enamels. It is said that a frit in which sodium silicate is used melts more rapidly than when silica and soda ash are used in the batch. Sodium metasilicate is used as a mill addition in enamels for aluminum. Lightweight insulating brick are made from vermiculite or perlite by bonding with sodium silicate and calcium carbonate or similar reactants. Silicates provide bonding strength at room temperature. Powdered silicates are used in the dry clay type bonding mortars to be mixed with water just before use. Liquids are used with plastic chrome ore and other agents to formulate various types of furnace cements. Dry hydrated silicates are used with chrome ore formulations for gunning mixes to be used in patching while furnaces are under heat. Silicates provide temporary tack until the fusion effect of the other

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Materials Handbook

ingredients comes into play. They give greater green strength and greater fired strength in air-set refractory specialties. SODIUM SILICATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com SODIUM TITANATE. A solid-state reaction is used to produce sodium titanate. Typical applications include powder products used as fluxes and arc stabilizers in welding rod and wire. The advantage of sodium titanate over other welding rod powders is the effect of the TiO2 (a slag former) and Na2O (arc stabilizer), which, in combination, provide good slag flow and sustained arc stability. This results in cleaner welds, better overall metallurgical properties and improved weld uniformity. Sodium titanate is also used in friction materials; nano-scale, high-purity applications for electronic sensors and radioactive waste remediation; and in medicine. SODIUM TITANATE SUPPLIERS

TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net SODIUM ZIRCONIUM SILICATE. An ingredient in glasses, glazes, frits, bodies and colors for glass and glaze decoration. It aids in densification of ceramic bodies, helps stabilize glaze colors and is particularly useful in glazes in combination with the more refractory double silicates. SOLID OXIDE FUEL CELL MATERIALS. In a solid oxide fuel cell (SOFC), oxygen ionized at the cathode migrates through the electrolyte toward the anode, where it reacts with the fuel to generate a voltage. Accordingly, the electrolyte must posses a high ionic conductivity and have no (or minimal) electronic conductivity. In addition, it must be nonporous to prevent short-circuiting of the reactive gases, and it must also be as thin as possible to minimize ohmic loss. Cubic zirconia stabilized with yttria (Y2O3), or YSZ, has been the most commonly used material of choice as a SOFC electrolyte. It is stable in the SOFC operating temperature range (8001000°C), its ionic conductivity is comparable with liquid electrolytes, it is stable in both reducing and oxidizing atmospheres, and it has a matching coefficient of thermal expansion (CTE) with the contacting layers. YSZ can be produced as a substrate by tape or slip casting, or it can be applied through electrochemical vapor deposition, plasma spraying, spray coating or dip coating onto a support made from anode or cathode material. Other electrolyte materials include scandium-doped zirconia (ScZ), samarium-doped ceria (SDC) and gadolinium-doped ceria (GDC). Fuel oxidation takes place at the anode. Anode requirements include good electronic conductivity, porosity, stability in a reducing atmosphere and a matching CTE to the electrolyte layer. Metals have an excellent electronic conductivity and can operate in reducing atmospheres, and nickel in particular is a favorable candidate due to its catalytic properties and affordability. However, nickel sinters at the high temperatures Supplier listings indicate paid advertising.

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of SOFCs, resulting in the unwanted densification of the structure. In addition, its CTE does not match that of the YSZ layer. These problems can be solved by combining nickel with YSZ into a Ni-cermet, and by firing the composite together with pore-forming resins. Remaining problems with nickel include the potential reaction with carbon from the fuel, and its sensitivity to sulfur and an oxidizing atmosphere—all of which contribute to the degradation of the cell’s performance. Alternative materials to Ni-YSZ-cermets include Cu-ceria, Ti-doped YSZ, and some perovskite materials. The cell components in a SOFC stack are connected to each other via interconnects (ICs), also referred to as bipolar plates. The interconnects fulfill several functions, including the distribution of fuel and air to the anode and cathode, respectively. They also serve as current collectors, and they provide a barrier between the anode and the cathode. Accordingly, an interconnect should have excellent electronic conductivity, oxidation-reduction resistance, matching CTEs to the contacting layers, chemical stability at the operating temperature, and no porosity to prevent the oxygen and hydrogen from mixing. Depending on the operating temperature, doped La-chromites, ferritic stainless steels and certain ceramics are candidate materials for ICs. The interconnects reflect the most expensive component of the fuel cell stack because of the materials and fabrication processes used. Both the metallic ICs, such as chromium alloys made by powder metallurgy, and ceramic ICs, such as zirconia multilayer tapes, that are used in precommercial units are rather costly. In an effort to reduce the material costs, various new steels are being researched that could provide corrosion resistance and temperature stability in the 800-850°C range. Cheaper steel grades will require lower operating temperatures. The seals must also have matching CTEs with the contacting materials. Additionally, they cannot react in any way with the stack components or with the gases, and they must be electronic insulators. Several materials, including glass, are being studied for use as sealing materials. Glass offers the advantage that its CTE can be tailored by adjusting the glass composition; however, it is brittle and tends to react with the cell components. Mica, which is a naturally occurring sheet silicate, is a candidate material in connection with compressive, non-bonding seals. At the cathode, oxygen is reduced to ions at a temperature range of 700-1000°C, depending on the type of fuel cell. The cathode requirements are similar to those of the anode— i.e., the cathode should have a high electronic conductivity and sufficient porosity to allow oxygen diffusion to the anode/electrolyte interface, it must be chemically stable with the contacting layers, it must have a matching CTE with the electrolyte, and it must possess a catalytic activity for oxygen reduction. In the tubular SOFC design, the cathode also provides mechanical support. The state-of-the-art cathode material used in conjunction with YSZ electrolytes is lanthanum manganite (LaMnO3). This perovskite-structured material is used for both tubular and planar SOFC designs. Lanthanum manganite has a high electrochemical activity for oxygen reduction, and it is thermally compatible (i.e., matching CTE) and chemically stable with the YSZ electrolyte. The electronic conductivity of lanthanum manganite is enhanced by doping it with Ca (LCM) or Sr (LSM). LSM can be manufactured through several methods, each of which offers various advantages and disadvantages in terms of performance and commercialization. These methods include solid-state reaction, sol-gel techniques, spray pyrolysis and co-precipitation. Another cathode material for YSZ electrolytes includes strontium doped lanthanum ferrite (LSF). A strong relationship exists between the LSM powder characteristics and the resulting cathode performance. The LSM powder should be a single-phase material with homogeneous particle morphology, narrow particle size distribution, defined stoichiometry and high crystallinity. These characteristics

SOLID OXIDE FUEL CELL MATERIALS

affect performance criteria such as polarization losses, oxygen-reduction activity and shrinkage behavior. At the heart of the matter are the so-called triple phase boundaries (TPBs), which are the contact surfaces between the ion conducting phase (YSZ), the electronic conducting phase (LSM) and the pores. A balanced ratio between these phases and the existence of a percolating system to the current collector on one hand, and to the electrolyte on the other, while minimizing possible reactions with the contacting interconnect, are crucial factors for the performance and efficiency of SOFCs. Therefore, the ability to control and adjust certain powder properties is critical. Studies have shown that an anistropic structure, such as a plate- or needlelike structure, can result in fluctuating shrinkage behavior between 20-34%, which can cause polarization losses and low electronic conductivity. In recent years, significant research has been aimed at lowering the operating temperature of SOFCs to the low range of 500-700°C and the intermediate range of 650-800°C. The performance of LSM-cathodes is limited to a temperature range of 8001000°C due to large over-potentials at lower temperatures; however, in combination with other materials, LSM-based cathodes are suitable for a wide range of operating temperatures. Lanthanum strontium cobalt ferrite (LSCF) is another formulation commonly used as a cathode. Additionally, composite cathodes based on mixtures of electrolyte and electrode materials (e.g., YSZ or GDC admixed with LSM, LSF or LSCF) have been shown to improve electrode performance at lower temperatures by increasing the volume of active sites available for electrochemical reactions. (See also FUEL CELL MATERIALS and LANTHANUM STRONTIUM MANGANITE.) SOLID OXIDE FUEL CELL MATERIALS SUPPLIERS POLYMER INNOVATIONS, INC. 2426 Cades Way Vista, CA 92081 (760) 598-0500 Fax: (760) 727-3127 Email: [email protected] Website: www.polymerinnovations.com PRAXAIR SPECIALTY CERAMICS 16130 Wood-Red Rd., Ste. #7 Woodinville, WA 98072 (425) 487-1769 Fax: (425) 487-1859 Email: [email protected] Website: www.praxair.com/specialtyceramics

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SPINEL

Phase purity: 100% spinel Mohs hardness: 8 Melting point: 2135°C Crystal density: 3.57 g/cm3 Optical transmission: 0.25-6 +m Refraction index: 1.718-1.723 Average particle size, chemically prepared ceramic powder: 3 +m CTE: 8.9 x 10-6 The name spinel also has more general usage, designating a structural group: XY2O4. A unit cell of this structure contains a face-centered cubic arrangement of 32 oxygen atoms which has 96 interstitial sites: 64 tetrahedral and 32 octahedral. Of these, only 24 are occupied: 16 octahedral and 8 tetrahedral. Five types of spinels are reported, characterized by the valence distribution of the constituent cations: 1. X2 + Y3 + 2O4 (e.g. TiMg2O4). 2. X4 + Y2 + 2O4 (e.g. MgAl2O4; FeFe2O4; ZnFe2O4). 3. X + Y3 + 0.5Y2O4 (e.g. (LiAl)0.5Al2O4; (LiFe)0.5Fe2O4). 4. X6 + Y + 2O4 (e.g. Li2MoO4; Ag2MoO4). 5. g - Y3 + 2O3 (e.g. g-Al2O3; g-Fe2O3). Spinels containing S= for O= also have been synthesized. In these general forms, two types of cation distributions are present: the normal and the inverse. The normal configuration has for the spinel unit cell (Mg2 + 8Al3 + 5D 16O33), the Mg2+ cations in the 8 tetrahedral sites and the Al3+ cations in the 16 octahedral sites. The inverse configuration has for the magnetite unit cell (Fe2 + 8Fe3 + 16O32) 8 of the 16 Fe3+ cations filling the 8 tetrahedral sites with the remaining 8 Fe3+ cations and the 8 Fe2+ cations filling the 16 octahedral sites in a random manner. The gamman oxides are special cases of this inverse configuration with, on the average, 2/3 vacant octahedral sites per unit cell. The major ceramic applications for spinels are the magnetic ferrospinels (ferrites), chromite brick and spinel colors (see table at right). Magnetic recording tape coated with _
SEM-COM CO. INC., TECHNICAL & ELECTRONIC GLASSES 1040 N. Westwood Ave. Toledo, OH 43607 (419) 537-8813 Fax: (419) 537-7054 Email: [email protected] Website: www.sem-com.com SPINEL. MgO-Al2O3 or MgAl2O4. Mol. wt. 142.26; sp. gr. 3.6-3.9; m.p. 2135°C. A mineral found in small deposits. It is formed by solid-state reaction between MgO and Al2O3 and is an excellent refractory showing high resistance to attack by slags, glass, etc. High-purity spinel is a chemically derived spinel powder made by the co-precipitation of magnesium and aluminum complex sulfates, with subsequent calcination to form the oxide compound. Purities range from 99.98-99.995%. Since it is chemically derived, the stoichiometries can be adjusted for virtually any MgO:Al2O3 ratio. The ceramic powders prepared by this process can be hot pressed into transparent window materials with exceptional IR transmission range. Properties of 1:1 spinel: Crystal system: cubic

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ALMATIS 501 W. Park Rd. Leetsdale, PA 15056 (800) 643-8771; (412) 630-2800 Fax: (412) 630-2900 Email: [email protected] Website: www.almatis.com C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

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SPINEL

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STAINS

Materials Handbook

SPINEL SUPPLIERS CONTINUED

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com SPODUMENE. A lithium aluminosilicate having the formula Li2O-Al2O3-4SiO2 and corresponding theoretical lithia content of 8%. A monoclinic pyroxene, spodumene has a melting point of 1420°C and undergoes a crystalline inversion from the natural alpha to beta form at 1080°C. This transition is accompanied by a volume increase of approximately onethird. Principal low-iron spodumene deposits are located in Canada and Western Australia, and produce spodumene concentrates with a typical analysis of: 65% SiO2; 25% Al2O3; 7.5% Li2O; 0.07% Fe2O3; 0.25% Na2O; 0.10% K2O; A deposit of high-iron spodumene is located in North Carolina. Lithium is the lightest, smallest and most reactive of the alkali metals. Additionally, lithium possesses the smallest ionic radius and the highest ionic potential. These factors combine to produce an extremely powerful flux that is exploited by the glass and ceramic industries in a variety of established methods and in new applications.

In frits and glazes, lithia is used to reduce the viscosity and thereby increase the fluidity of the coatings. This reduces maturing times and lowers firing temperatures. Small amounts of lithia increase gloss. In electrical porcelain applications, lithia produces a high-strength glaze that is resistant to weathering. More recently, crystallized glazes have been developed for coating of low expansion bodies. Spodumene is an ideal raw material for introducing lithia into frits and glazes but may be limited in some applications by its alumina content. The lowering of the thermal expansion coefficient to an almost negligible level by development of the beta spodumene phase is the basis for pyroceramic (oven-to-tableware) production. In fully vitrified porcelain bodies, spodumene, in combination with nepheline syenite or feldspar, has been shown to significantly reduce firing temperatures. The availability and acceptance of a 4.8% Li2O glassgrade spodumene has enabled the bulk glass industry (container, flat and fiberglass) to evaluate lithia as a means of increasing factory efficiencies. Glass lithia concentrations of 0.10-0.25% are being utilized worldwide to increase furnace capacity, decrease melting temperatures and increase production efficiencies. Claims of lithia restricting emission of sulphates to the atmosphere are under investigation. Future applications are to establish lithia as a flux in various vitreous and semivitreous ceramics, in chemically toughened glass and as a slag viscosity modifier in the metallurgical industries.

Low-Iron Spodumene Sand & Flour Excellent Product Availability Improve production efficiencies and thermal shock properties in glass, coatings and ceramic products

SPODUMENE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com SQUEEGEE OIL. Squeegee oil, or squeegee medium, is a liquid vehicle designed especially for mixing with vitrifiable colors to make a paste suitable for application on ceramic ware by the silk screen stencil process. Squeegee oil is not completely different from paint vehicles, except that it must have the property of burning off cleanly in the lehr, kiln or furnace without leaving any tar or carbon deposit to darken or blister the color. In present practice, the oils must have an accurately determined rate of drying to dry satisfactorily on the ware but not clog the screen. They also must dry hard enough on the ware to permit handling, and must make a smooth paste that goes easily through the screen in sufficient quantity to give good coverage. SQUEEGEE OIL SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com STAINS. Ceramic colors, usually one of the transitions metals in combination with other elements, applied to a body, glaze or porcelain enamel as an addition to the body, glaze or porcelain enamel composition. STAIN SUPPLIERS

Innovative Mineral Specialists

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FUSION CERAMICS INC. P.O. Box 127, Carrollton, OH 44615 (330) 627-2191 Fax: (330) 627-2082 Email: [email protected] Website: www.fusionceramics.com

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STAINS

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TALC

STAIN SUPPLIERS CONTINUED

MASON COLOR WORKS INC. 250 E. Second St., Box 76 East Liverpool, OH 43920 (330) 385-4400 Fax: (330) 385-4488 Email: [email protected] Website: www.masoncolor.com STANNATE. A salt of stannic acid. See specific compounds for additional details. STANNIC OXIDE. SnO2. By far the largest commercial outlet for stannic oxide is in the ceramic industry, where it is used either as a white pigment (i.e. opacifier) or as a constituent of colored pigments in the glazes applied to, for example, crockery, sanitaryware and decorative wall tile. The most important tin pigments are the tin-vanadium yellows, the tin-antimony blue-grays, the tinchrome lilacs (all based on the SnO2 rutile lattice) and the tin-chrome pinks (based on the calcium-tin-silicon oxide sphene lattice). The pigments are prepared by first coprecipitating SnO 2 and TiO 2 as mixed gels in the manner developed for catalyst production. These are then sintered at 5001250°C to produce the solid solutions that are doped by impregnation of the gel oxides with nitrate solutions of the selected ions. Five different compositions of SnO 2TiO2 solid solutions have been treated in this way with Co 2+, Cu 2+, Fe 3+, Ni 2+, Mn 2+, V 5+ and Sb 5+. The colors obtained to date in these studies are shown in the table at the top of the page. STANNOUS CHLORIDE. SnCl2. Mol. wt. 189.61. Solutions of this material, when applied to glass, ceramic and porcelain enamel surfaces and cured with proper thermal treatment, provide surface conductivity or resistance for surface heating. STEARATES. A class of organic materials used chiefly as drytype lubricants for the dry pressing of technical ceramic products. Calcium, magnesium and zinc are used. They give some internal bonding strength but their prime function is better lubrication. (See LUBRICANTS.) STRONTIUM CARBONATE. SrCO3. Mol. wt. 147.6; sp. gr. 3.63.7; soluble in acids and slightly soluble in water, especially if carbonated. Strontium carbonate starts to decompose to the oxide at 800°C in air, but in a CO2 atmosphere evolution of carbon dioxide does not begin until ~1220°C. Strontium carbonate is mined as the mineral strontianite in Germany, but most of the strontium carbonate marketed is prepared from the mineral celestite (SrSO4) either by boiling in a solution of ammonium or sodium carbonate or by fusion with sodium carbonate. Strontianite is a preferable source, but it is not nearly so common as celestite, which occurs in England, Germany and Sicily. America’s strontium production is also available to the ceramic industry. Celestite is important due to its greater abundance and lower cost. Perhaps the greatest potential resources of celestite lie in vast areas of Texas, Mexico, California, Arkansas, Utah and Washington. In an investigation of the effects of various oxides on china bodies, it was found that strontium-containing bodies have less pinholing or blistering than calcium, zinc, magnesium or barium bodies. The fact that strontium carbonate is extremely easy to decompose and that magnesium carbonate and barium carbonate are very stable may explain the almost complete absence of blistering in the former case and excessive blistering in the others. This is

no doubt due to the carbon dioxide being completely driven off in the former case before vitrification begins. Strontium oxide in bodies imparts a whiteness at cone 9 which improves considerably at cone 10. It gives some very tough bodies of high porosity and low shrinkage, some showing in a rattler test loss as low as 0.5%. Its principal disadvantage is cost. Koenig claims strontium carbonate facilitates the development of low temperature glazes. By the use of this oxide a good cone 01 glaze was obtained that contained no zinc oxide. He reported that the heat shock resistance was better than would be anticipated from the glaze compression of 03 min. This fact is probably related to increased bodyglaze interaction, as this glaze is high in basic oxides not contained in the body and has only 0.5 equivalent of NaKO. This cone 01 glaze was reported to have an excellent gloss and mirror-like texture:

}

0.26 PbO 0.28 CaO 0.10 MgO 0.13 BeO 0.13 SrO 0.05 Li2O 0.05 NaKO

0.27 Al2O3 0.31 B2O3

{

2.80 SiO2

Substituting SrO for either CaO or ZnO in many respects yielded superior glazes. In the case of PbO a satisfactory leadless glaze was produced only by a long soaking period. Thus, it is quite apparent that satisfactory leadless glazes might be developed with strontia. Increasing the multiplicity of the RO group would lessen the apparent tendency of crystallization, and a decrease in solubility would be expected as compared with normally soluble lead glazes. High lime-containing glazes, often necessary to carry some colors, can be improved by extending their firing range (within the firing limits of the color oxide) through the addition of strontia. Normally viscous zirconium-containing sanitaryware glazes can be smoothed out through the use of strontia. The development of glazes for low temperature vitreous bodies can be materially aided through the use of strontia. The added fluidity provided by strontia when replacing calcium and/or barium should promote interface reaction, improve glaze fit, while offsetting the slightly higher thermal expansion evidenced in some cases in the dinnerware glaze tested. Strontia additions to such glazes should materially increase glaze hardness and lower the solubility. Scratch resistance should be improved when replacements are made, especially at the expense of calcium and barium, which would be due, in part, to the earlier reaction of strontia enabling the glaze to clear with a minimum of pits. STRONTIUM FLUORIDE. SrF2. Mol. wt. 125.63; m.p. 1190°C. Cubic, white crystals have a density of 2.44 g/cm3. Slightly soluble in water, soluble in hot HCl. STRONTIUM FLUORIDE SUPPLIERS

STRONTIUM TITANATE. SrTiO3. M.p. 2080°C. Cubic crystal structure. Insoluble in 140°F fresh water after 100 days. Maximum sintered density: 96% of theoretical (5.11 g/cm3). Thermal conductivity (at 94% theoretical density) 2.78 Btu/ ft/ft2/hr/°F at 212°F. Methods of compounding: (1) from mixed strontium carbonate and titanium dioxide, (2) from mixed strontium oxalate and titanium dioxide and (3) from strontium titanyl oxalate. Strontium titanate is then prepared by calcining the three starting materials in air for 3 hr at 2000-2200°F. Strontium titanate is a high dielectric constant material (225-250) that at lower temperatures has a temperature coefficient of dielectric constant somewhat higher than that of calcium titanate. Strontium titanate bodies can be dry pressed (60008000 psi) or slip cast and are fired to vitrification at a peak temperature of 2450-2550°F. Strontium titanate can be used by itself or in combination with barium titanate in applications for capacitors and other parts. The power factor of strontium titanate is unusually high at low frequencies with a great improvement in power factor in the neighborhood of 1 MHz. The thermal expansion of strontium titanate is linear over a wide temperature range (100-700°C). SUPERABRASIVES. Superabrasives are synthetic diamond and cubic boron nitride crystals used in sawing, grinding, machining, drilling, and polishing applications in many industries. (See also ABRASIVES.) SUPERABRASIVE SUPPLIERS

UK ABRASIVES INC. 3045 Mac Arthur Blvd. Northbrook, IL 60062 (847) 291-3566 Fax: (847) 291-7670 Email: [email protected] Website: www.ukabrasives.com

T

ALC. 3MgO-4SiO2-H2O. Talc is a hydrous magnesium silicate, with the composition 63.4% SiO2, 31.9% MgO and 4.7% H2O when found in pure form. It is an extremely soft mineral with a Mohs hardness of 1, has a platy structure and it is naturally hydrophobic. Talc occurs as a relatively pure massive mineral in Montana, Australia and China. Elsewhere it occurs in conjunction with magnesite (Vermont, Quebec, Ontario and Finland), with tremolite and serpentine in New York and with chlorite in France and Austria. In many ceramic applications, the presence of non-talc minerals such as chlorite and tremolite are beneficial. Talc products of greatest use in ceramics are mined in Texas, New York and Montana. Typical chemical analyses of these ores are shown in the following table:

BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com STRONTIUM OXIDE. SrO. Mol. wt. 103.63; m.p. 2430°C. Cubic, gray-white crystals (density 4.7 g/cm3) dissociate in water. Slightly soluble in alkalis.

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Talc used in ceramics is usually mined, sorted, crushed, and milled to 95-99% -200 mesh. Milling is done in roller mills for softer massive ores while ball mills are used for harder tremolitic products. Products are shipped as a dry powder, mostly in 50 pound bags but the use of supersacks is increasing and larger customers use bulk rail or truck. Some product is calcined prior to shipping and this will usually improve dry pressing characteristics. The major applications for talc in North America are tile and hobbyware bodies, cordierite catalyst supports, kiln furniture and electrical porcelains. There are minor applications in electronic packaging, sanitaryware, dinnerware and glazes. In traditional tile and hobbyware bodies, bodies containing 30 to 60% talc are fired at low temperatures (below cone 2), and long cycles (>12 hours) to form porous bodies, which are then glazed and refired. Talc products containing tremolite are preferred for their better pressing and permeability characteristics. White firing New York and Texas talc dominate this market and some calcined product is also used. If purer or platier talc products are used, wollastonite has to be added to improve pressing and permeability. The tile industry today is moving to fast fire technology, and this is reducing talc to a minor component in these single fire formulations. Cordierite bodies can be formed from pure talc (44%), plastic kaolin (41%) and alumina (15%) or from 50/50 mixtures of kaolin and chlorite. Cordierite has very low coefficients of thermal expansion (CTE), which accounts for its use in kiln furniture and automotive catalysts supports. Firing temperatures have to be much higher for the pure talc containing bodies. The talc based body is preferred for automotive catalyst supports; although it is more expensive, it is possible to get better control of minor elements such as iron and calcium which have a major impact on CTE. For kiln furniture, chlorite based bodies are preferred because of their lower cost and better high temperature creep resistance. In kiln furniture modified with mullite to improve shock resistance, French sourced chloritic talc is utilized. For steatite bodies used in electrical insulating applications, pure talc along with about 10% plastic kaolin and 10% barium carbonate is fired at cone 12-13 to form low loss bodies. Low calcium and alkali metal levels are critical, so only high purity Montana talc is used. Consistency is also critical, since many parts have high tolerances and shrinkage requires close control. Talc is used as a flux for high alumina ceramics, sanitaryware and dinnerware. It is a low cost source of magnesium in these applications and helps to produce less porous bodies at lower firing temperatures. TALC SUPPLIERS UNIMIN CORP. 258 Elm St. New Canaan, CT 06840 (800) 243-9004 (N. America); (203) 442-2500 Fax: (800) 243-9005 (N. America) Email: [email protected]

TANTALUM AND COMPOUNDS OF. See specific compound listings for details. TANTALUM AND COMPOUNDS OF SUPPLIERS

CHIVINE RESOURCES INC. 1 Bestor Ln., P.O. Box 7383 Bloomfield, CT 06002 (860) 216-2221 Fax: (860) 383-8993 Email: [email protected] Website: www.chivine-us.com TANTALUM CARBIDE. TaC, Ta2C. The ore tantalum carbide with a congruent melting point is TaC. It is dark-to-light brown in color with a metallic luster. Pure crystals without nitride or oxide films are gold in color. Ta 2C melts incongruently and is gray with a metallic luster. Ta 2C melts at 3400°C; m.p. of TaC has been reported to be as high as 4820°C. TaC burns in air with a bright flash and is only slightly soluble in acids. Its X-ray density is 14.53 g/cm3; Mohs’ hardness is 9+; Brinell hardness is 840; Knoop microhardness is 1952 kg/mm 2. Microhardness also has been reported as 1800 kg/mm2 (50 g load). Modulus of elasticity is 41.5 x 108 psi; tensile strength at room temperature is 2000-4000 psi. The mean linear CTE of randomly oriented, polycrystalline TaC is 8.2 x 10-6/°C. The specific electrical resistivity of TaC at room temperature is 200 +ohm-cm. TANTALUM ETHOXIDE. Ta(OC2H5)5. Tantalum ethoxide is a clear, colorless, slightly viscous liquid at room temperature. It is soluble in most organic solvents, very moisture sensitive, and yields Ta2O5 upon reaction with water. Its main use is in the production of oxide films—primarily for thin-film optical and semiconductor applications—where it is transparent in the visible and near-IR and reflects in the IR region. Ta(OC2H5)5 has also been used in low-pressure chemical vapor deposition (LPCVD) systems to produce films over fairly large areas. This process is being developed for the production of advanced metal-oxide semiconductor (MOS) memory devices and dynamic random-access memory (DRAM). The advantage of the deposited Ta2O5 film is a dielectric constant higher than that obtained by many commonly used dielectric materials. This property permits smaller capacitor dielectrics and subsequently smaller features on semiconductor devices. The deposited films often need to be annealed in oxygen to produce the desired properties. (See also NIOBIUM ETHOXIDE.) TANTALUM OXIDE. Ta2O8. Decomposes at 1470°C; CTE (30630°C) 16.4 x 10-7/°C. Ta2O8 and the tantalates of sodium, cadmium and other common elements have been found to possess ferroelectric properties, many of the combinations having Curie temperatures of 200-275°C. TANTALUM OXIDE SUPPLIERS

TANNIC ACID SUPPLIERS

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TAPE, CERAMIC. Flat films of ceramic powders mixed with organic binders that can be laminated and fired to make ceramic substrates for a number of applications, ranging from multilayer ceramic capacitors (MLCCs) and low temperature co-fired ceramics (LTCCs) to lithium batteries, fuel cells, oxygen separators and thermistors. Additional applications include ceramic body armor, optical films, medical films used as drug delivery systems, and microporous membranes. TAPE, CERAMIC SUPPLIERS POLYMER INNOVATIONS, INC. 2426 Cades Way Vista, CA 92081 (760) 598-0500 Fax: (760) 727-3127 Email: [email protected] Website: www.polymerinnovations.com TELLURIUM. Te. At. wt. 127.61; sp. gr. 62.4. A semimetallic element of the sulfur group that exists in two forms: (1) grayish-white, lustrous, brittle crystalline solid, and (2) dark gray to brown, amorphous powder that changes to the crystalline form upon heating. Melts at 452°C, boils at 1390°C. Insoluble in water and hydrochloric acid, but soluble in nitric and sulfuric acids. Recovered as a byproduct of copper. Tellurium can produce yellow, green and blue colors in glass, and its use as a colorant in glass and dinnerware is occasionally reported. TERBIUM OXIDE. Tb4O7. Mol. wt. 747.7. Soluble in acids, only slightly soluble in water. As ignited in air, the oxide has the composition Tb4O7, but other terbium compounds are related to the sesquioxide Tb2O3 (mol. wt. 366.4). It is one of the rare earths and is available in purities up to 99.9%. Tb4O7 is a chocolate-colored powder with a mol. wt. of 747.72 and a cubic crystal structure. Its major impurity is gadolinium oxide. Tb2O3 melts at 2387°C. A major application is in Faraday rotation glass for laser applications and as an activator ion in a Gd2O3S crystal for X-ray screen image intensification. TERBIUM OXIDE SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com TERRA ALBA. CASO4 2H2O. Pure white, uncalcined gypsum. (SEE GYPSUM.) TERRA ALBA SUPPLIERS

Source: Cerac Inc., www.cerac.com/pubs/proddata/ethoxds.htm.

TANNIC ACID. (See BINDERS.)

ESPRIX TECHNOLOGIES 7680 Matoaka Rd. Sarasota, FL 34243 (941) 355-5100 Fax: (941) 358-1339 Website: www.esprixtech.com

Materials Handbook

H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

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LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com TETRAETHYL ORTHOSILICATE. (C2H5O)4-Si. Mol. wt. 208.37; sp. gr. 0.94; b.p. 168°C; m.p. 85°C; vapor density 7.2 (air = 1). A white liquid which decomposes slowly in water. Autoignition Supplier listings indicate paid advertising.

TETRAETHYL ORTHOSILICATE

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TIN OXIDE

temperature: 500°F. An alkoxide used as the source of silica for producing high-purity silica glass from the sol-gel process. Also used when making high-purity metal oxide frits from solgels. Other uses include as a bonding agent for investment castings, crucibles and refractory shapes.

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TETRAETHYL ORTHOSILICATE SUPPLIERS GELEST INC. 11 E. Steel Rd. Morrisville, PA 19067 (215) 547-1015 Fax: (215) 547-2484 Email: [email protected] Website: www.gelest.com THERMAL BARRIER MATERIALS. Papers, coatings, foils or other materials designed to resist high temperatures. THICKENER. An additive, such as silica or calcium carbonate, used to increase viscosity of coating materials. THICKENER SUPPLIERS ACTIVE MINERALS INTERNATIONAL LLC, ATTAPULGITE DIV. 6 N. Park Dr., Ste. 105 Hunt Valley, MD 21030 (800) 233-4482; (410) 825-2920 Fax: (815) 333-2997 Website: www.activeminerals.com THULIUM OXIDE. Tm2O3. Mol. wt. 386.8. Soluble in acids, very slightly soluble in water. A rare earth available in purities of 99 and 99.9%. Its primary use is as a radiation source in portable X-ray equipment. TIN OXIDE. SnO2. (Stannic oxide.) Mol. wt. 150.7; sp. gr. 6.6-6.9; m.p. 1150°C; softening temperatures 500-600°C. White powder which does not decompose at temperatures normally used for firing ceramic glazes. Insoluble in water and most aqueous acids, but soluble in fused alkalies. Bonded with small amounts of Fe, Ni, Zn, Co, Mn and Cu, it gives a nonwetting ceramic with K = 8; power factor ~0.05% and high dc resistivity. Preferred bond is 1-3% Bi2O3. Tin oxide occurs in nature as cassiterite, mined in Bolivia, the Netherlands, India, Thailand and China. Tin oxide made from the metal is produced by several processes, all involving direct thermal oxidation. Tin oxide also is made commercially by chemical solution of tin, followed by precipitation of tin hydrate, which is then converted to the oxide by calcining. Tin oxide has long been an important opacifier in all types of opaque glazes. Amounts of 2-8% SnO2 are used in glazes, although normal requirements are 4-5% (except for lowtemperature glazes, which may require larger additions). Tin oxide has the property of imparting high luster and fluidity to glazes—as little as 1-2% having a marked effect in imparting gloss. Tin oxide is an important constituent of ceramic stains for enamels, glazes and bodies. Pink and maroon colors are obtained with tin oxide, chrotin oxide and vanadium compounds. Tin oxide also is an important color stabilizer for some of the tin-bearing pink, gray, yellow and blue coloring stains for glazes. For this purpose, it is used as a mill addition to the glazes. From 1-2% is usually added for color stabilization. Tin and gold chlorides are used to produce purple of Cassius; this color is not stable above 800°C, but it can be used as an overglaze color with a flux of red lead, borax and flint. Similar use is made of tin oxide and gold chloride in brilliant red jewelry enamels. This oxide was formerly an important opacifier for enamels on cast iron and sheet steel, although it has been replaced by substitute materials such as antimony, zirconium, titanium and other compounds. The substitution has been largely for economic reasons, as tin oxide is still recognized as the superior opacifier from the standpoint of quality for both glazes and enamels. The use of high opacity frits for sheet steel has eliminated tin oxide as a mill opacifier, but additions of about 1% are used as a mill addition in some of the acid resistant enamels for dry process enameling. In dry process enamels, tin oxide has been replaced by sodium antimonate and antimony oxide as the frit opacifier in most commercial applications. In glass, stannic oxide is an important addition to cadmium-selenium and gold colors, especially reds. Stannous oxide, SnO, is a necessary ingredient in the development of copper ruby glass and is also used to produce black glasses. Stannous oxide is a black powder with a mol. wt. of 134.7. It is also a component of ruby-red and black glasses. Tin oxide, because of its resistance to solution in most glasses, especially those high in lead oxide, is being used for refractories for special applications, such as glass feeders, and conducting electrodes for electrical resistance melting of glass. Submit equipment definitions online at www.ceramicindustry.com/materialshandbook

In Natural and Frit Glaze Suspensions: • Acti-Gel®208 greatly improves adhesive strength by >80% which helps to reduce surface defects and glaze chipping from handling and shipping. • Acti-Gel®208 eliminates other mineral thickeners and reduces cellulose ethers in glaze formulations. • Acti-Gel®208 should be used without Phosphates Dispersants such as SHMP or STPP which chelate excess ions thereby de-activating Acti-Gel®208. • By using Acti-Gel®208 to reduce Cellulose Ethers and eliminate Phosphate Dispersants, the negative effects of Sodium are greatly

reduced, allowing for increased adhesion strengths and reduced surface defects. • Acti-Gel®208 allows the glaze to dry rapidly without cracking. • Acti-Gel®208 is added directly to the mill for ease of dispersion and for ease of glaze removal from ball mill. • Acti-Gel®208 based glazes are highly stable and can sit, without settling or hardpacking, for >30 days. • Acti-Gel®208 works efficiently in Suspensions from 25% to 80% solids. • Acti-Gel®208 contains no sulphates

In Ceramic Body Formulations: • Acti-Gel®208 is an excellent flow aid, binder and reinforcing agent in extrusion and dry press applications.

Acti-Gel®208 features and benefits: • Lowers Formulation Costs! • Increases adhesion strength! • Dewaters Rapidly! • Allows more efficient use and faster batch addition times. • Excellent Anti-Settling and Anti-Sag properties. • Low yield point of gel structures allows for quick, easy flow under shear conditions.

• Ultra fine particle size gives excellent performance in spray and curtain coating applications. • Reduces extrusion pressures and improves forming and green strength. • Very low free crystalline silica (less than 1%), Grit Free. • Low free Moisture: Typical is 5%-8% FM.

For more information and a FREE sample, visit our web site at www.activeminerals.com or call 410-825-2920.

ActiveMinerals I N T E R N AT I O N A L , L LC

6 NORTH PARK DR, SUITE 105, HUNT VALLEY, MD 21030 CERAMIC INDUSTRY ³ January 2012

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Materials Handbook TITANIUM CARBIDE SUPPLIERS CONTINUED

TIN OXIDE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com TITANATE CERAMICS. Materials based on various multiple oxides of titanium dioxide. (See also TITANIUM DIOXIDE.) TITANIUM CARBIDE. TiC. A very hard, refractory material finding increasing usage for wear-resistant applications and for applications requiring material with good thermal shock resistance. Titanium carbide is available in both a very high purity grade and a technical grade. The difference between the grades is largely a matter of carbon content. Granular material and powder in various sizes (down to average particle size of a few micrometers) can be obtained. Titanium carbide can be formed either by bondless hot pressing or by powder pressing methods. The material is finding use in cermet components such as jet engine blades and cemented carbide tool bits. Titanium carbide has a relatively low electrical resistivity (1 x 10-4) and can be used as a conductor of electricity, especially at high temperatures. Extreme hardness of titanium carbide makes it suitable for wear-resistant parts such as bearings, nozzles, cutting tools, etc. It also serves for special refractories under either neutral or reducing conditions. TiC theoretically contains 20.05% C and is light metallic gray in color. It is chemically stable, being almost inert to hydrochloric and sulfuric acids. In oxidizing chemicals, such as aqua regia and nitric or hydrofluoric acids, TiC is readily soluble. It also dissolves in alkaline oxidizing melts. When heated in atmospheres containing nitrogen, nitride formation occurs above ~1500°C. TiC is attacked by chlorine gas and is readily oxidized in air at elevated temperatures. The density of TiC is 4.94 g/cm3, Mohs hardness is 9+, microhardness is 3200 kg/mm2, and modulus of elasticity is 45 x 106 psi. The modulus of rupture at room temperature has been reported as 73,500-124,000 psi for materials sintered at 2600-3000°C. Hot modulus of rupture values are given as 15,850-17,200 psi at 982°C and 80009400 psi at 2200°C. TiC’s melting point is 3160°C, and electrical resistivity at room temperature is 180-250 +ohm-cm. It can be used as a conductor at high temperatures. CTE between room temperature and 593°C is 4.12 x 10-6/°F. Thermal conductivity is 0.041 cal/cm•s/°C. TITANIUM CARBIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

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H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com TITANIUM DIBORIDE. TiB2. Mol. wt. 69.54; stoichiometric theoretical density 4.52 g/cm3; hexagonal (AlB2) crystal structure; melting point 2980°C. Titanium diboride is stable in HCl and HF acid, but decomposes readily in alkali hydroxides, carbonates and bisulfates. It reacts with hot H2SO4 and is easily soluble in HNO3 + H2O2 and HNO3 + H2SO4. Although TiB2 can be produced by several synthesis methods, the most common processes for the production of large quantities are: 1) 2TiO2 + C + B4C2TiB2 + 2CO2 and 2) 2TiO2 + 5C + 2B2O3 2TiB2 + 5CO2. The as-synthesized powder is gray to dark gray in color, while the sintered parts are metallic gray. Sintered parts of titanium diboride are usually produced by either hot pressing, pressureless sintering or hot isostatic pressing. Hot pressing of titanium diboride parts is conducted at temperatures >1800°C in vacuum or 1900°C in an inert atmosphere. Hot pressed parts generally have a final density of >99% of theoretical. Typical sintering aids used for hot pressed parts include iron, nickel, cobalt, carbon, tungsten and tungsten carbide. Pressureless sintering of TiB 2 is a less expensive method for producing net shape parts. Due to the high melting point of titanium diboride, sintering temperatures in excess of 2000°C often are necessary to promote sintering. Several different sintering aids have been developed to produce dense pressureless sintered parts by liquid phase sintering. A combination of carbon and chromium, iron or chromium carbide can be used as a sintering aid to produce pressureless sintered parts with a final density >95% of the theoretical density. Boron carbide also is added to inhibit grain growth during sintering. These sintering aids as well as atmospheric conditions can be used to lower the sintering temperature necessary for full densification. Typical mechanical properties for hot pressed titanium diboride include a flexural strength of 350-575 MPa, a Knoop hardness of 2600 kg/mm2 and a fracture toughness of 5-7 MPa •m -1/2. The mechanical property values are dependent on the type of fabrication method used (pressureless sintering vs hot pressing), the purity of the synthesized powder and the amount of porosity remaining in the finished part. The elastic modulus of titanium diboride can range from 430-500 GPa and the Poisson ratio is 0.18-0.20. Titanium diboride has a room temperature electrical resistivity of 12 x 10-6 ohm-cm and a thermal conductivity of 80-100/mK. Titanium diboride is used for a variety of structural applications, including ceramic armor, nozzles, seals, wear parts and cutting tool composites. Titanium diboride also has shown exceptional resistance to attack by molten metals, including molten aluminum. This, in addition to its intrinsic electrical conductivity, makes it a useful material for such applications as metallizing boats, molten metal crucibles and Hall-Heroult cell cathodes. TiB2 can be combined with a variety of other nonoxide ceramic materials, such as silicon carbide (SiC) and titanium carbide (TiC), and oxide materials, such as alumina (Al2O3), to increase the mean strength and fracture toughness of the matrix material.

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TITANIUM DIBORIDE SUPPLIERS

®

CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com

ESK CERAMICS GMBH & CO. KG Max-Schaidhauf-Str. 25 Kempten 87437 Germany (49) 831-56180 Fax: (49) 831-5618345 Email: [email protected] Website: www.esk.com H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com TITANIUM DIOXIDE. TiO2. Mol. wt. 80; sp. gr. 3.9-4.2; m.p. ~3370°F; refractive index 2.52-2.76. Insoluble in water, dilute acids, organic acids, dilute alkalis. Soluble in hot concentrated sulfuric acid and hydrofluoric acid. Manufactured mainly by digesting ilmenite, the principal ore, in concentrated sulfuric acid; separating hydrous titanium dioxide obtained through thermal hydrolysis; then purifying, treating and calcining the hydrous oxide to titanium dioxide, which is finally milled. In addition to ilmenite, rutile ore and titanium slag obtained from the electric furnace smelting of titaniferous iron ore also are starting materials. Another method for manufacturing titanium dioxide is the chloride process wherein natural rutile ore is chlorinated to form titanium tetrachloride, which is purified, vaporized and reacted with oxygen at elevated temperature to form the dioxide. The great bulk of the titanium dioxide of commerce is in the form of the strongest white pigment known. Unsurpassed opacity of this pigment is mainly the result of optimum particle size and refractive index higher than that of any other white pigment substance. Titanium dioxide pigment is available in two primary classes according to the two crystal structures of anatase and rutile and, in addition, in different types according to use. Pigment having the rutile crystal structure has generally 20-40% greater opacity than the anatase form. Average refractive indices for these two classes are 2.72 for rutile and 2.52 for anatase. Titanium dioxide is a most important ceramic finish coat for sheet metal products. The opacity of this enamel Supplier listings indicate paid advertising.

2012 Edition

imparted by titanium dioxide has lowered film thickness of these finishes to the range of organic coatings while retaining the durability of porcelain. These enamels are self-opacified. That is, titanium dioxide is not dispersed as an insoluble suspension during smelting nor is it added at the mill. Rather, titanium dioxide is taken into solution during smelting of the batch and is held in supersaturated solution through fritting. Upon firing the enamel, titanium dioxide crystallizes or precipitates from the glassy matrix. Composition of these enamels and their processing is so controlled as to provide the proper particle size and particle size distribution to make the high refractive index of titanium dioxide most effective. Thus far, in titania enamels having the most desirable properties, the precipitated titanium dioxide is anatase. While the rutile crystal structure is preferred in titanium pigments for many different nonceramic compositions, in titania enamels appreciable rutile gives rise to objectionable color. Care must be exercised in selecting TiO2 because pigment qualities are not characteristic of nonpigmentary titanium dioxide made especially for titania porcelain enamels. This grade flows freely in the dry state and eliminates sticking and balling up that often characterizes titanium dioxide pigments. It also has maximum TiO2 content, being free from additives and harmful colorants used in pigments. As a result, nonpigmentary titanium dioxide is preferred for titania porcelain enamels. The addition of small amounts of titanium dioxide pigment to the enamel mill is not for primary opacification, but usually to increase hiding power of the enamel slip or to regulate and stabilize reflectance of certain compositions. Prior to the advent of titania porcelain enamel, the chief ceramic use of manufactured titanium dioxide was in dry process enamels for cast iron. In these, titanium dioxide, carried in solution in the glass, provided resistance to household acids and other acidic substances with opacity gained from other opacifiers, such as antimony oxide. Thus, for these enamels, nonpigmentary grade titanium dioxide pigment is preferred. Contrasted with self-opacified titania enamels in which titnaium dioxide is often 20 wt% of the batch, dry process enamels carry only 4-8 wt%. Titanium dioxide pigment is, however, used primarily as an opacifier, added at the mill, for glass enamels and for porcelain enamels for aluminum. In both these enamels, nonpigmentary titanium dioxide is smelted into the composition to produce acid and chemical resistance. Titanium dioxide is used in glazes to affect acid resistance, color and texture. In certain fritted glazes maturing at about cone 2, unusual semimatte and textured finishes are secured through adding pigmentary titanium dioxide at the mill. Crystals of sphene (CaO-SiO2-TiO2) resulting from the added titanium dioxide and the calcium and silica of the frit, account for these effects. Much research is being conducted on glazes analogous to titania porcelain enamels self-opacified by titanium dioxide. To glass, nonpigmentary titanium dioxide imparts interesting properties, including high refractive index for optical and other glass, such as reflective beads. It also intensifies and brightens colored transparent glasses, especially those utilizing ceria as colorant. Can shrink the fibers of fiberglass. Where whiteness and sharp clean tints are not important, mineral or natural rutile finds use in some of the above applications, such as dry process enamels for cast iron and fiberglass. This titanium dioxide mineral, largely because of impurities, is used in minor amounts to color certain bodies and glazes. Dielectric applications. Available in three mineral forms: rutile, anatase and brookite; distinguished from each other by differences in crystal modification, index of refraction, density, etc. Only the rutile form, which decomposes at 1640°C, is used for dielectric purposes. Rutile bodies are used in either the pure form or with

TITANIUM DIOXIDE

minor additions of various materials for: capacitors (substitutes for mica, paper and electrolytics), temperature compensating (tc) capacitors, trimmer condensers, bypass condensers, filter and power circuits, and as fillers for resins and low melting glasses. Manufacture involves dry mixing or tempering with water (up to 10%), dry pressing at 5000-10,000 psi or extrusion; or, for complex parts, slip casting (deflocculate with 1% ethylene diamine or 1% tannic acid with 10% NH4OH) followed by firing the parts to vitrification with approximately a 2 hr soak at peak temperature (24002450°F). Results have shown that in firing titanium dioxide bodies, a particular fired structure yields the best allaround dielectric properties and may be obtained in a body having a porosity of zero or nearly zero. As a capacitor, pure rutile has a dielectric constant of 173 parallel to the principal axis and 89 perpendicular to this axis. Most polycrystalline bodies produced commercially have a value of 85-96 at room temperature when measured statically or in the trequency range of 60 Hz to 3000 MHz. Bodies are characterized by a fairly large negative coefficient of dielectric constant 750-800 (25-86°C), which may be made less negative by the addition of other compounds, such as magnesium titanate or zirconium dioxide (though with a decrease in dielectric constant). Power factor is ~0.5-0.7% at 60 Hz, dropping off rapidly to 0.05% at 10 kHz and remaining at that figure to 100 MHz. Resistivity (25°C) is approximately 1014 ohm-cm for commercial grade TiO 2 and 1016-1018 ohm-cm for extremely pure TiO2. Ordinary dielectric strength is 150-200 V/mil, but proper design of the test piece can raise this to 600-700 V/mil for commercially pure TiO2 and about 50% higher for very pure TiO2. Temperature compensating capacitors based on TiO2 have dielectric constants varying from 15-85 and temperature coefficients varying from +120 ppm/C through zero to -750 ppm/C (most negative body has highest TiO2 content). The compensators are necessary in all radio receivers where the exact frequency of resonance of the resonant circuit changes slightly with changes in temperature. These undesirable changes are corrected by introducing a reactive component having a temperature coefficient of the opposite sign and of such a value as to offset the undesired change with temperature. Extraordinary duplicable and close tolerances are available, in some cases as accurate as 3-5 ppm. Capacitances range from 1-1100 pF. Trimmers or trimmer condensers employing TiB2 bodies are used for minute adjustments of capacitance. Normally the rotor consists of a TiO2 body. Parts are made with extreme accuracy, and are usually supplied in one of three temperature coefficient types. The base is a low loss ceramic composition. Mechanical and physical properties of TiO2 include relatively low strength (MOR 18,000-22,000 psi; tensile strength 6000-8000 psi), low thermal conductivity (0.14 cal/cm/s/C) and a CTE (for rutile) of 7-9 x 10-6/°C. Rutile (TiO2) can be prepared in the form of single crystals by the Verneuil (flame fusion) technique. Slightly reduced rutile is an n-type semiconductor with an energy gap of 3.05 eV and electron mobilities of ~1.0 cm2/Vs at room temperature. TITANIUM DIOXIDE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com

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TUNGSTEN CARBIDES

TITANIUM DIOXIDE, HIGH-PURITY. Titanium dioxide with purity levels of 98-99.99%. (See TITANIUM DIOXIDE.) TITANIUM DIOXIDE, ULTRAFINE. Titanium dioxide powders in the nanoparticle size range (1-200 nanometers) feature pure crystallinity, a high surface area and high thermal stability. Applications include environmental and industrial catalysis, optical glass and ceramics. TITANIUM NITRIDE. TiN. Mol. wt. 61.91; m.p. 2930°C; density 5.29 g/cm3. Bronze red crystals insoluble in water and acids. TITANIUM NITRIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com TRICALCIUM PHOSPHATE. Ca3(PO4)2. Sp. gr. 3.18; m.p. 1670°C. White amorphous powder insoluble in cold water, decomposes in hot water. Tricalcium phosphate has been successfully used to replace tin oxide in raw, leadless sanitaryware glazes maturing at cone 8 or higher, resulting in satisfactory color, permanent opacity, brilliance and texture. It works well both in low-alkali and high-alkali glazes at this temperature range, but produces no opacity in glazes maturing in the range cone 2-6. TRICALCIUM PHOSPHATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com TUNGSTEN CARBIDES. W2C, WC. W2C is a gray-green powder of density 17.20 g/cm3; m.p. 2860°C. WC is metallic gray with density 15.50 g/cm3; m.p. 2865°C. W2C is slightly soluble in acids and burns readily in air. Although comparatively resistant to most acids, it is dissolved by hot HNO3. It reacts readily and is completely oxidized in oxygen at 500°C. Microhardness of W2C is 3000 kg/mm2; modulus of elasticity is 60.5 x 106 psi. Electrical conductivity is 80 +ohm-cm at room temperature and 125 +ohm-cm at 2000°C. The compound WC is resistant to acids and is not attacked at room temperature by mixtures of HF and HNO3. It reacts with fluorine with the formation of a flame at room temperature and is oxidized when heated in air. Microhardness values of 2500 kg/mm2 are reported; Knoop values average 1307 with maximums of 2105 noted. Tensile strength of sintered WC bars, 50,000 psi; modulus of elasticity, 102.5 x 106 psi (20°C); MOR at room temperaCERAMIC INDUSTRY ³ January 2012

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YTTRIUM OXIDE

Materials Handbook

UNDERGLAZE COLOR SUPPLIERS CONTINUED ture, 80,000 psi (hot pressed specimens); electrical conductivity, 40% that of pure tungsten. TUNGSTEN CARBIDE SUPPLIERS

Advanced Material Specialists, Inc.

HAI ADVANCED MATERIAL SPECIALISTS INC. 1688 Sierra Madre Cir. Placentia, CA 92870 (877) 411-8971 Fax: (877) 411-8778 Email: [email protected] Website: www.haiams.com TUNGSTEN CARBIDE FIBER. Tungsten carbide (WC) fiber/ filament is a continuous 50-, 100- or 150-micron filament with high hardness and density. It is well-suited for wear and impact erosion applications, along with use in armorpiercing ammunition and as an effective neutron reflector. TUNGSTEN OXIDE. (Tungsten trioxide.) WO3. Mol. wt. 232; sp. gr. 7.2; m.p. 1473°C. Soluble in hot alkalies and hydrofluoric acid, insoluble in other acids. Obtained from the minerals scheelite, CaWO4; wolframite, (FeMn)WO4; and ferberite, FeWO4. Tungsten oxide, being a canary yellow powder, may be used for yellow glazes, but is liable to produce blue glazes by conversion of the trioxide, WO3, into the octoxide, W3O3. Tungsten oxide is occasionally used as a crystallizing agent in crystalline glazes, and it also acts as a catalyst in the formation of tridymite and cristobalite from other forms of silica. Tungstic acid, H2WO4, also has been used as a glaze colorant. Single crystals of WO3 of good purity are reported to show ferroelectric properties at liquid air temperature. TUNGSTEN OXIDE SUPPLIERS H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

U

NDERGLAZE COLORS. Underglaze colors are prepared calcined pigments designed to be applied to bisque ware and later covered with a glaze. Underglaze colors must have high intensity and high stability to resist the intensive corrosive effect of the glaze during firing, and must be fine enough to be incorporated smoothly with the oil-based vehicles ordinarily used in applying, to give smooth and attractive designs. UNDERGLAZE COLOR SUPPLIERS

LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

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MASON COLOR WORKS INC. 250 E. Second St., Box 76 East Liverpool, OH 43920 (330) 385-4400 Fax: (330) 385-4488 Email: [email protected] Website: www.masoncolor.com TREBOL Ave. Los Angeles No. 3408 Ote. Fracc. Coyoacan Monterrey, N.L. 64510 Mexico (52) 81-8126-2300; (52) 81-8126-2321 Fax: (52) 81-8126-2303 Email: [email protected] Website: www.gtrebol.com

W

ETTING AGENT. Media that dry out commonly fail to rewet properly for a number of reasons. Waxes, resins, organic acids and other chemicals present in organic-media components are inherently water-repellent. Hydrophobicity is a condition that prevents water from adhering to and moving uniformly into and through a medium. The reason media do not wet consistently is that the particle surfaces and pores within these media are constantly changing every time they undergo wet-to-dry cycles. A wetting agent imparts a “film” to all of the particle surfaces within the medium and allows the medium to retain its ability to uniformly wet-out for several days to several weeks. (See also ADDITIVES, CHEMICAL.)

Source: “Raw Materials, Chemicals, Polymers and Additives Handbook,” ASI, March 2009, p. 50.

WETTING AGENT SUPPLIERS ZSCHIMMER & SCHWARZ INC., U.S. DIVISION 70 GA Hwy. 22W Milledgeville, GA 31061 (478) 454-1942 Fax: (478) 453-8854 Email: [email protected] Website: www.zschimmer-schwarz.com WOLLASTONITE. CaSiO3. (Calcium silicate.) A naturally occurring calcium metasilicate. Wollastonite imparts low moisture expansion, reduced drying and firing shrinkage, higher fired strength, improved heat shock, faster firing, easy pressing, better bonding, and superior electrical properties to bodies, glazes, porcelain enamels and frits. Wollastonite applications in the ceramic industry can be classified in two general groups: (1) a replacement for flint and limestone and (2) a material for producing bodies and glazes of superior properties. Wollastonite is mined in various locations throughout the world. The oldest mined sites are located in New York state. Wollastonite is a natural mineral and has almost the chemical formula of theoretical calcium silicate. Its most outstanding characteristics are its brilliant whiteness, its chemical and physical uniformity, and its acicular nature, which is easily controlled by mechanical means from a granular material to acicular crystals. Because it is relatively new in the minerals field, all its uses are not known, but already it has proven successful in making brighter and smoother glazes, better low-loss dielectric bodies, a good flux for stronger welding rod coatings, an excellent material for semivitreous bodies of the wall tile type and in applications where good thermal shock properties are of primary importance. Among the many other ceramic applications in which wollastonite can be used are: glazed porous ceramics of

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nearly every kind, dinnerware, ovenware, artware, structural clay products, terra cotta, sanitaryware, chemical stoneware, ceramic-bonded abrasives, refractories, high alumina bodies, spark plugs, electrical porcelains, frits and investment castings. WOLLASTONITE SUPPLIERS LAGUNA CLAY CO., CA/OH/FL 14400 Lomitas Ave. City of Industry, CA 91746 (800) 452-4862; (626) 330-0631; (740) 439-4355 OH; (407) 365-2600 FL Fax: (626) 333-7694 CA Email: [email protected] Website: www.lagunaclay.com

NYCO MINERALS INC. 803 Mountain View Dr., P.O. Box 368 Willsboro, NY 12996 (518) 963-4262 Fax: (518) 963-4187 Email: [email protected] Website: www.nycominerals.com

R. T. VANDERBILT, CO. INC. P.O. Box 5150 Norwalk, CT 06856-5150 (203) 853-1400 Fax: (203) 853-1452 Email: [email protected] Website: www.rtvanderbilt.com

Y

TTERBIUM OXIDE. Yb2O3. Mol. wt. 394.1; density 9.17 g/cm3; soluble in acids, only slightly soluble in water. A rare earth available in purities up to 99.9%.

YTTERBIUM OXIDE SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com YTTRIUM NITRATE. Available in two forms: hexahydrate and tetrahydrate. The hexahydrate (Y[NO3]3 • 6H20) has a mol. wt. of 383.01 and a density of 2.68. It is very soluble in alcohol, ether and nitric acid. The tetrahydrate (Y[NO3]3 • 4H20) is a reddish-white prism. It has a mol. wt. of 346.98, a density of 2.68, and is soluble in alcohol, nitric acid and cold water. Due to its solubility and decomposition upon calcination, ytrrium nitrate is used as a precursor to ytrrium oxide. YTTRIUM OXIDE. Y2O3. Mol. wt. 225.81; m.p. 4865°F; density 5.03 g/cm3; soluble in acids, but only slightly soluble in water. Yttrium is not a rare earth but always occurs with them in minerals because of similar general chemistry. Applications are in electrically conducting ceramics, refractories, insulators, phosphors, glass, special optical glasses and other ceramics. Supplier listings indicate paid advertising.

2012 Edition

White powder has cubic crystal structure and small amounts of dysprosium oxide, gadolinium oxide and terbium oxide as impurities. Yttria can be compounded into polycrystalline as well as single crystal garnets for use in microwave generation and detection devices. Such materials are of importance to microwave technology because they exhibit both good dielectric and magnetic properties, which can be controlled through compositional variations. Yttria-stabilized zirconia can be used to produce a high quality diamond substitute for jewelry or a rugged sensor for measuring oxygen in automotive exhaust, depending on the method of fabrication. Nd:YAG single crystal rods find many applications as lasers in industry and in research. Y2O3 can be used (with Sc, La and Cs oxides) with TiO2 bodies for better control of properties than experienced with alkaline earths. In combination with europium oxide, yttria is used to make the red phosphor in color television picture tubes. Combined with ZrO2, it makes good high temperature refractories. It also is used in silicon nitride as a sintering aid. YTTRIUM OXIDE SUPPLIERS

Advanced Material Specialists, Inc.

HAI ADVANCED MATERIAL SPECIALISTS INC. 1688 Sierra Madre Cir. Placentia, CA 92870 (877) 411-8971 Fax: (877) 411-8778 Email: [email protected] Website: www.haiams.com PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK INC., CHEMICALS 45 Industrial Pl. Newton, MA 02461-1951 (617) 630-5906 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com Y-TZP. Yttria tetragonal zirconia polycrystal (Y-TZP) is a fine grained ceramic used in special engineering applications that benefit from its high density, excellent wear resistance and fine grian size, such as fiber optic ferrules. High purity fine reactive coprecipitated zirconia powders containing 3 mole% yttria are used to produce Y-TZP ceramics.

YTTRIUM OXIDE

Y-TZP SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com TOSOH USA INC. 3600 Gantz Rd. Grove City, OH 43123-1895 (866) 844-6953 Fax: (614) 875-8066 Email: [email protected] Website: www.tosohusa.com

Z

INC OXIDE. White powder. Mol. wt. 81.4; sp. gr. 5.6; sublimes at 1800°C. Insoluble in water, soluble in strong alkali solutions and in acids. The rubber industry is the largest consumer of zinc oxide, accounting for more than 50% of the market. Zinc oxide is most effective as an activator of accelerators in the vulcanization process. The chemical industry has been opening new markets for zinc oxide. Examples are lubricating oil additives, water treatment and catalysts. For photocopying, photoconductivity is a unique electronic property of zinc oxide. The paint and coatings industry used to be the second largest consumer of zinc oxide. But shipments declined as the industry switched from linseed oil exterior house paints to latex paints. Since 1950, however, that situation has been changing, and more zinc oxide-containing latex paints are available. In the ceramic industry, zinc oxide is used in the manufacture of glasses, glazes, frits, porcelain enamels and magnetic ferrites. Here, the largest consuming plants are in the tile industry. There are two production types of zinc oxide, namely the French process and the American process. In the French process, zinc metal is vaporized in large containers by external heating. In an adjoining off-take pipe or combustion chamber, the vapor is burned off in the air to fine zinc oxide powder. In the American process, oxidized ores of roasted sulfide concentrates are mixed with anthracite coal and smelted in a Wetherill-type flat bed furnace. The coal, plus the products of partial combustion, particularly CO, reduce the ore to metallic zinc, which issues as a vapor. In the off-take pipe, the vapor, together with the gases from the coal, is burned under controlled conditions and piped to the bag house where the oxide is collected. American process material contains sulfur compounds of zinc and provides a slower cure rate that is preferred by some rubber manufacturers. One ceramic grade of zinc oxide has these properties: sp. gr. 5.6; apparent density 1201 kg/m3; weight 5595.5 kg/m3. Typical chemical analysis (in %): 99.5 ZnO, 0.05 Pb, 0.02 Fe, 0.01 Cd, 0.02 S (total), 0.10 HCl (insoluble), 5 ppm magnetic iron. In glass, zinc oxide reduces the coefficient of thermal expansion, thus making possible the production of glass products of high resistance to thermal shock. It imparts high brilliance of luster and high stability against deformation under stress. As a replacement flux for the more soluble alkali constituents, it provides a viscosity curve of lower slope. Specific heat is decreased and conductivity increased by the substitution of zinc oxide for BaO and PbO. A 1% addition of zinc oxide to tank window glass lowers the devitrification temperature and improves chemical resistivity while maintaining good workability for drawing. It is used consistently in high-grade fluoride

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ZINC OXIDE

opal glass, in which it greatly increases opacity, whiteness and luster by inducing precipitation of fluoride crystals of optimum number and size. Apparently, zinc oxide makes its contribution to opacity through reduction of the primary opacifiers. It is used in optical glasses of high barium content to reduce their tendency to crystallize on cooling. The resistance of phosphate glasses to chemical attack is improved by the presence of zinc oxide. About 10% zinc oxide assists in the development of the characteristic color of cadmium sulfoselenide ruby glass, although its exact function is obscure. Zinc oxide is used in many types of glazes, its function varying according to the particular composition in which it is included. In general, it provides fluxing power, reduction of expansion, prevention of crazing, greater gloss and whiteness, a favorable effect on elasticity, increased maturing range, increased brilliance of colors and correction of eggshell finish. It is useful in preventing volatilization of lead by partial substitution for CaO, since high CaO tends to satisfy SiO2, leaving PbO in a more volatile form. Glaze crawling, when attributable to the action of zinc oxide in the glaze, is due to shrinkage and can be avoided through the use of calcined zinc oxide. Calcined zinc oxide, by virtue of its greater density and decreased bulkiness, allows for less prefire shrinkage of the glaze. In Bristol glazes for earthenware products, zinc oxide in combination with alumina produces both opacity and whiteness to a fair degree, provided the lime content is low. The use of zinc oxide in wall tile glazes is very general; the zinc oxide content of certain types being 10% or more. Small amounts are used in gloss or bright tile, while higher percentages are used where it is desired to develop a highly pleasing matte finish. Crystalline glazes are produced by loading to supersaturation with zinc oxide. Zinc compounds crystallize when the solution reaches a critical fluidity and, if cooled rapidly after formation, the crystals are held in suspension. These crystals may be tinted if various pigmentary oxides are incorporated in the glaze composition. The more homogenous a zinc crystalline glaze is, the more perfectly the crystals will separate out. The value of zinc oxide in crystalline glazes lies in its unusual property of crystallizing as a silicate instead of an oxide. In semiporcelain glazes zinc oxide forms opaque silicates. It reduces the melting point of the mass and tends to reduce boiling of the glaze during firing. It increases the firing range, improves resistance to crazing and generally makes the glaze more flexible. It has no opacifying power when used in borosilicate glazes. In general, zinc oxide has a beneficial effect upon colored glazes, but should be used with caution because of its adverse effect with certain coloring agents. It alters the colors obtained with underglaze decorations, destroying some and improving others. It lightens normally strong blues and greens. With the light greens of copper, it produces cleaner, more brilliant colors. Zinc oxide is commonly used in dry-process cast iron porcelain enamels in amounts of 0.5-1% to 14%. In general, low lead content implies high zinc and vice versa. Its specific functions are to increase fusibility, improve luster, contribute to opacity and whiteness, reduce expansion and increase extensibility. It is probably a little stronger as a flux than is lime, but does not produce the sudden fluidity characteristic of lime. Gloss may be decreased by using an excessive amount of zinc oxide or by attempting to introduce it into a composition not adapted to its use. It is thought that loss of gloss is due to the crystallization of zinc compounds, which in turn are due to the state of balance of the enamel ingredients. Of great benefit to producers of cast iron enamels is the relative nontoxicity of zinc oxide. A recent use for zinc oxide is its application to the manufacture of magnetic ferrites, which have been developed over the past 25-30 years. They usually are composed of CERAMIC INDUSTRY ³ January 2012

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ZIRCONIA-ALUMINA

ferric oxide in combination with zinc oxide (of high chemical purity) and any one or more of several other oxides of bivalent metals. The amount of zinc oxide used varies from 10-35%, depending upon the characteristics desired in the finished magnetic ferrite. Having as their prime properties high permeability and low hysteresis, they are used in the field of electronics for such devices as high frequency transformer cores for television receivers. Zinc oxide crystals can exhibit strong piezoelectric properties. Normally recognized as an n-type semiconductor, it has a resistivity less than 103 ohm-cm. When doped with lithium, resistivity rises to 1012 ohm-cm and it exhibits piezoelectricity about four times that of quartz. ZINC OXIDE SUPPLIERS AMERICAN CHEMET CORPORATION P.O. Box 437 Deerfield, IL 60015-4374 (847) 948-0800 Fax: (847) 948-0811 Email: [email protected] Website: www.chemet.com ZOCHEM INC. 1 Tilbury Ct. Brampton, ON L6V 2L8 Canada (905) 453-4100 Fax: (905) 453-2920 Email: [email protected] Website: www.zochem.com

Materials Handbook

ZINC PHOSPHATE. Zn3(PO4)2-H2O. A material used in dental cements and in the production of phosphors. ZINC PHOSPHATE SUPPLIERS BASSTECH INTERNATIONAL 300 Grand Ave. Englewood, NJ 07631 (201) 569-8686 Fax: (201) 569-7511 Email: [email protected] Website: www.basstechintl.com ZINC ZIRCONIUM SILICATE. M.p. 2080°C. Unique zirconium opacifier ideally suited for artware or low-temperature glazes where opacity and color brilliance are desired. Is generally blended with other zirconium products in medium- and hightemperature glazes. ZINC ZIRCONIUM SILICATE SUPPLIERS TREBOL Ave. Los Angeles No. 3408 Ote. Fracc. Coyoacan Monterrey, N.L. 64510 Mexico (52) 81-8126-2300; (52) 81-8126-2321 Fax: (52) 81-8126-2303 Email: [email protected] Website: www.gtrebol.com ZIRCON. ZrSiO4. Sp. gr. 4.5-4.6; specific heat 0.55 J/g/C (0.131 Btu/lb/F); Mohs’ hardness 7.5-8.0. Fine, white, mineral powder with a tetragonal structure. Is chemically

inert and stable to very high temperatures (liquidus >4000°F). Zircon has excellent thermal properties. Its thermal conductivity is 14.5 Btu/ft2/hr/°F/in. and CTE is 1.4 x 10-6. Dielectric constant is high, averaging 12.7, while power factor is <0.1%, which is desirable for low loss applications. Average index of refraction: 2.0. Zircon’s extremely high thermal conductivity and chilling action makes it very useful in controlling directional solidification and shrinkage in heavy metal sections. The rounded grain requires a minimum of binder or clay thus allowing only the refractory and nonwetting surface of zircon to contact the molten metal. Its fine grain size gives a superior casting surface with which the molten metal refuses to react resulting in absence of burning and a quick, clean shakeout. Zircon sand is used as refractory bedding material for heat treating metal parts. It is used as a sealing medium for prevention of atmospheric leaks around doors and parts of heat treating furnaces. Also, it is a high quality, uniform sandblasting medium for metal preparation prior to plating, enameling or buffing. The heavy, rounded grains give consistent peening without stray digs or gouges to mar the finish. The tough, resilient grains resist breakdown and loss. ZIRCON SUPPLIERS ALUCHEM INC. One Landy Ln. Reading, OH 45215 (513) 733-8519 Fax: (513) 733-3123 Email: [email protected] Website: www.aluchem.com

PRINCE MINERALS INC. 233 Hampshire St., Ste. 200 Quincy, IL 62301 (646) 747-4200 Fax: (217) 228-0466 Website: www.princeminerals.com TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net TREBOL Ave. Los Angeles No. 3408 Ote. Fracc. Coyoacan Monterrey, N.L. 64510 Mexico (52) 81-8126-2300; (52) 81-8126-2321 Fax: (52) 81-8126-2303 Email: [email protected] Website: www.gtrebol.com ZIRCONATES. Any salt of zirconic acid. ZIRCONIA-ALUMINA. Aggregate materials containing varying concentrations of zirconia and alumina. They are used mostly as filler components in ceramic parts manufacturing operations. Their attributes are relatively low costs, thermal tolerance and white color.

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2012 Edition

ZIRCONIA-ALUMINA ZIRCONIA MULLITE (FUSED) SUPPLIERS CONTINUED

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ZIRCONIA, YTTRIA STABILIZED

ZIRCONIA, PARTIALLY STABILIZED SUPPLIERS CONTINUED

ZIRCONIA-ALUMINA SUPPLIERS RIO TINTO ALCAN, SPECIALTY ALUMINAS Paragon Two-Ste. 110, 6150 Parkland Blvd. Cleveland, OH 44124-4185 (800) 321-3864 Fax: (440) 460-2604 Email: [email protected] Website: www.specialty-aluminas.riotintoalcan.com

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com ZIRCONIA, ENGINEERING GRADE. Zirconia that is suitable for use in a variety of mechanical and industrial applications. It is usually formulated for high wear, impact, chemical/corrosion and temperature resistance. ZIRCONIA, ENGINEERING GRADE SUPPLIERS

SAINT-GOBAIN ZIRPRO 1 New Bond St., P.O. Box 15137 Worcester, MA 01606 (800) 243-0028 Fax: (508) 795-2380 Email: [email protected] Website: www.zirpro.com

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com ZIRCONIA, PARTIALLY STABILIZED. PSZ. Transformationtoughened material consisting of a cubic zirconia matrix with 20-50 vol% free tetragonal zirconia added in the matrix. The material is converted into the stabilized cubic crystal structure using oxide stabilizers (magnesia, calcia, yittria). The conversion is accomplished by sintering the doped zirconia at 1700°C. Magnesia stabilized zirconia exhibits serrated plastic flow during compression at room temperature. The flow stress is strain rate sensitive. Several different grades are available for commercial use, and the material’s properties can be tailored to fit many applications. One typical PSZ used for applications requiring maximum thermal shock resistance has a four-point bend strength of 600 MPa; K Ic of 8-15 MPa•m1/2; Wiebull modulus of 21; compressive strength of 1800 MPa; modulus of elasticity of 205 GPa; and Poissons ratio of 0.23. Physical properties include a density of 5.70 g/cm3; CTE of 8.6 x 10-6/°C; and thermal conductivity of 2.2 W/mK. PSZ is being used experimentally as heat engine components, such as cylinder liners, piston caps and valve seats. Vanadium impurities from fuel oil can cause zirconia destabilization, and Na, Mg and S impurities can cause yittria to dissociate from yittria stabilized zirconia. Another area of interest for PSZ is in bioceramics, where it has use in surgical implants. The material has shown no measurable change in density and surface toughness, while showing less than 10% loss in strength when immersed in 0.9 saline solution for 1000 hr. (See ALUMINA, TRANSFORMATION TOUGHENED.) ZIRCONIA, PARTIALLY STABILIZED SUPPLIERS

TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net

SAINT-GOBAIN ZIRPRO 1 New Bond St., P.O. Box 15137 Worcester, MA 01606 (800) 243-0028 Fax: (508) 795-2380 Email: [email protected] Website: www.zirpro.com

ZIRCONIA, HYDROXIDE. A nontoxic amorphous white powder that is insoluble in water but soluble in dilute mineral acids. It is primarily used as an intermediate for the manufacture of zirconium compounds, as well as in pigments, glass and dyes. Source: www.wikipedia.org

ZIRCONIA MULLITE (FUSED). (See MULLITE, ZIRCONIA.) ZIRCONIA MULLITE (FUSED) SUPPLIERS C-E MINERALS 901 E. 8th Ave. King of Prussia, PA 19406 (610) 768-8800 Fax: (610) 337-8122 Email: [email protected] Website: www.ceminerals.com

TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net

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TOSOH USA INC. 3600 Gantz Rd. Grove City, OH 43123-1895 (866) 844-6953 Fax: (614) 875-8066 Email: [email protected] Website: www.tosohusa.com ZIRCONIA POLYCRYSTAL. (See ZIRCONIA, PARTIALLY STABILIZED.) ZIRCONIA, REFRACTORY GRADE. Zirconia that is suitable for use in applications where resistance to high temperature, corrosion and erosion are required. ZIRCONIA, REFRACTORY GRADE SUPPLIERS

SAINT-GOBAIN ZIRPRO 1 New Bond St., P.O. Box 15137 Worcester, MA 01606 (800) 243-0028 Fax: (508) 795-2380 Email: [email protected] Website: www.zirpro.com

TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net

WASHINGTON MILLS P.O. Box 423, 1801 Buffalo Ave. Niagara Falls, NY 14302 (800) 828-1666 Fax: (716) 278-6650 Email: [email protected] Website: www.washingtonmills.com ZIRCONIA, YTTRIA STABILIZED. Yttria-stabilized zirconia (YSZ) is a zirconium-oxide based ceramic, in which the particular crystal structure of zirconium oxide is made stable at room temperature by an addition of yttrium oxide. These oxides are commonly called “zirconia” (ZrO2) and “yttria” (Y2O3). Source: Wikipedia, http://en.wikipedia.org/wiki/Yttria-stabilized_zirconia

ZIRCONIA, YTTRIA STABILIZED SUPPLIERS PANGEA INTERNATIONAL LIMITED Unit 303, No. 3., Lane 259 Huangjincheng Rd. Shanghai 201103 China +86 21 62082768 Fax: +86 21 54995682 Email: [email protected] Website: www.pangea-intl.com

CERAMIC INDUSTRY ³ January 2012

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ZIRCONIUM CARBIDE

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ZIRCONIUM OXIDE

Materials Handbook ZIRCONIUM NITRIDE SUPPLIERS CONTINUED

ZIRCONIUM CARBIDE. ZrC. Mol. wt. 103.22; reported melting points, 3035 and 3570°C; X-ray density 6.44 g/cm3. Theoretical carbon content: 11.64%. Gray metallic colored; insoluble in HCl but soluble in H2SO4 and in mixtures of concentrated HNO3 and HF. Zirconium carbide is readily oxidized in air at elevated temperatures, and its powder is pyrophoric at room temperature. It is readily decomposed by all oxidizing agents and halogens. ZrC reacts with nitrogen to form zirconium nitride. ZrC’s mechanical properties include: tensile strength 11,700-14,450 psi at 900°C, and 12,950-15,850 psi at 2,200°F; Mohs’ hardness 8-9; and microhardness 2,600 kg/mm2 (50 g load). Its specific electrical resistivity at room temperature is 70 +ohm-cm. ZIRCONIUM CARBIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com ZIRCONIUM CARBONATE. (ZrO2)2 CO2, nH2O. A moist, white powder used as an intermediate for the synthesis of Zrbased chemicals.

80-100 W/mK. The thermal expansion coefficient of ZrB2 is 5.5 x 10-6/K from room temperature to 1000°C. Consolidation of ZrB2 powder into parts is accomplished by hot pressing or pressureless sintering. When sintered to full density, ZrB2 has a metallic gray appearance. The as-received powder is combined with 1-5% sintering aid, such as iron, nickel, cobalt, carbon, tungsten or tungsten carbide. Hot pressing techniques for this material are similar to those used for the consolidation of titanium diboride. Hot pressing is conducted at temperatures >1800°C in vacuum or >1900°C in an inert atmosphere, such as argon. Densities of the hot pressed parts are usually >98% of the theoretical density. Hot pressed, dense ZrB2 exhibits an average flexural strength of 200-375 MPa and a Vickers hardness of 1200-2200 kg/mm2. The elastic modulus of this material is 440-460 GPa, the shear modulus 192-206 and the Poisson ratio 0.13-0.14. All of these properties are dependent on the purity and density of the sintered ZrB2 part. Similar to titanium diboride, ZrB2 is wet by molten metals but is not attacked by them, making it a useful material for molten metal crucibles, free-formed nozzles, EDM electrodes, Hall-Heroult cell cathodes and thermowell tubes for steel refining. This last use is one of the largest uses of zirconium diboride. Other uses for ZrB2 include electrical devices and as an antioxidant in carbon-bonded refractories (e.g., in submerge entry nozzles). ZIRCONIUM DIBORIDE SUPPLIERS H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com

ZIRCONIUM CARBONATE SUPPLIERS ZIRCONIUM DIOXIDE. (See ZIRCONIUM OXIDE.)

SAINT-GOBAIN ZIRPRO 1 New Bond St., P.O. Box 15137 Worcester, MA 01606 (800) 243-0028 Fax: (508) 795-2380 Email: [email protected] Website: www.zirpro.com ZIRCONIUM DIBORIDE. ZrB2; Mol. wt. 112.8; stoichiometric theoretical density 6.09 g/cm3; hexagonal (AlB2) crystal structure; melting point 3040°C. ZrB2 powder can be produced by several different processing routes: 1) reaction of the elemental components (Zr + 2BZrB2), 2) electrolysis of ZrO2 and B2O3 (2ZrO2 + 2B2O32ZrB2 + 5O2) and 3) reduction of zirconia with carbon and boron carbide or boric oxide (2ZrO2 + C + B4C 2ZrB2 + 2CO2 or 2ZrO2 + 5C + 2B2O32ZrB2 + 5CO2). Zirconium diboride is oxidation-resistant at temperatures <1000°C and reacts slowly with nitric, hydrochloric and hydrofluoric acids. It reacts with aqua regia and hot sulfuric acid, as well as with fused alkalis, carbonates and bisulfates. Zirconium diboride has a typical room temperature electrical resistivity of 9.2 x 10-6 ohm-cm and is superconductive at temperatures less than 2K. ZrB2 has a thermal conductivity of

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ZIRCONIUM NITRIDE. ZrN. Zirconium nitride has excellent erosion resistance and exhibits high hardness, good lubricity and ductility, making it an attractive coating material. It takes the form of a yellow crystalline powder or an attractive pale goldencolored coating. Zirconium nitride is used as a hard coating for machine tools like drill bits and burs. These coatings are deposited by physical vapor deposition. Zirconium nitride-coated tools are suited to non-ferrous metal applications like the machining of aluminum alloys, brasses, copper alloys and titanium. Source: www.AZoM.com.

ZIRCONIUM NITRIDE SUPPLIERS ADVANCED MATERIAL TECHNOLOGIES 3240 Boatman’s Mtn. Rd. Morristown, TN 37814 (423) 318-8878 Email: [email protected] H.C. STARCK GMBH, CERAMIC POWDERS P.O. Box 2540 Goslar 38615 Germany (49) 5321-751-3145 Fax: (49) 5321-751-4145 Email: [email protected] Website: www.hcstarck.com

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H.C. STARCK, AMCP TRADING LLC 45 Industrial Pl. Newton, MA 02461 (617) 630-5818 Fax: (617) 630-5919 Email: [email protected] Website: www.hcstarck.com ZIRCONIUM OXIDE. (Zirconia.) ZrO2. Mol. wt. 123.22; sp. gr. 5.7; m.p. 2700°C; low thermal conductivity. Pure zirconia is monoclinic at room temperature and changes to the denser tetragonal form at about 1000°C. CTE for the cubic or stabilized form is 10.5 x 10-6/°C; for the monoclinic or pure form, 6.5 x 10-6/°C up to 1200°C. Most producers make a 70-80% cubic material having a CTE of ~5.5 x 10-6 and showing no inversion. However, some stabilized ZrO2 compositions are being produced with CTEs of 5.1 x 10-6/°C. Zirconium oxide occurs in nature as the mineral baddeleyite, which is mined in Brazil and Africa. However, zirconia is usually produced from the mineral zircon, ZrO2-SiO2, which is available in large quantities. Various grades of zirconia are made from zircon; ranging from 75% zirconium oxide up to extremely pure, hafnium-free material of >99% purity. As an opacifier, zirconium compounds are used in glazes and porcelain enamels. Zirconium dioxide is an important constituent of ceramic colors and an important component of lead-zirconate-titanate electronic ceramics. Pure zirconia also is used as an additive to enhance the properties of other oxide refractories. It is particularly advantageous when added to high-fired magnesia bodies and alumina bodies. It promotes sinterability and, with alumina, contributes to abrasive characteristics. To prepare useful formed products from zirconium oxide, stabilizing agents such as lime, yttrium or magnesia must be added to the zirconia, preferably during fusion, to convert the zirconia to the cubic form. Most commercial stabilized zirconia powders or products contain calcium oxide as the stabilizing agent. The stabilized cubic form of zirconia undergoes no inversion during heating and cooling. Stabilized zirconia refractories are used where extremely high temperatures are required. The low thermal conductivity (about 8 Btu/ft2/hr/in./°F at 1800°F) ensures low heat losses, and the high melting point permits stabilized zirconia refractories to be used continuously or intermittently at temperatures of >4000°F in neutral or oxidizing atmospheres. Above 3000°F, in contact with carbon, zirconia is converted to zirconium carbide. Zirconia is of much interest as a construction material for nuclear energy applications because of its refractoriness, corrosion resistance and low nuclear cross section. However, zirconia normally contains about 2% hafnia, which has a high nuclear cross section. The hafnia must be removed before the zirconia can be used in nuclear applications. Zirconia is available in several distinct types. The most widely used form is stabilized in cubic crystal form by a small lime addition. This variety is essential to the fabrication of shapes since the so-called unstabilized, monoclinic zirconia undergoes a crystalline inversion on heating that is accompanied by a disruptive volume change. Zirconia is not wetted by many metals and is therefore an excellent crucible material when slag is absent. It has been used very successfully for melting alloy steels and the noble metals. Zirconia refractories are rapidly finding application as setter plates for ferrite and titanate manufacture, and as matrix elements and wind tunnel liners for the aerospace industry.

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2012 Edition

ZIRCONIUM OXIDE

³

ZTA

ZIRCONIUM OXIDE SUPPLIERS CONTINUED foundry binders, refractories, adhesives, textiles and antiperspirants.

ZIRCONIUM OXIDE SUPPLIERS

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ZIRCONIUM SILICATE. (Zircon.) ZrSiO4. M.p. 2550°C; softening temperature 850-950°C. (See ZIRCON.) CERADYNE INC. 3169 Red Hill Ave. Costa Mesa, CA 92626 (714) 549-0421 Fax: (714) 549-5787 Email: [email protected] Website: www.ceradyne.com

Z-TECH LLC 8 Dow Rd. Bow, NH 03304 (603) 228-1305 Fax: (603) 228-5234 Email: [email protected] Website: www.z-techzirconia.com

Advanced Material Specialists, Inc.

HAI ADVANCED MATERIAL SPECIALISTS INC. 1688 Sierra Madre Cir. Placentia, CA 92870 (877) 411-8971 Fax: (877) 411-8778 Email: [email protected] Website: www.haiams.com

SAINT-GOBAIN ZIRPRO 1 New Bond St., P.O. Box 15137 Worcester, MA 01606 (800) 243-0028 Fax: (508) 795-2380 Email: [email protected] Website: www.zirpro.com TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net

ZIRCOA INC. 31501 Solon Rd. Solon, OH 44139 (440) 248-0500 Fax: (440) 248-8864 Email: [email protected] Website: www.zircoa.com ZIRCONIUM OXYCHLORIDE. ZrOCl28H2O. Zirconium oxide dichloride, commonly called zirconium oxychloride, is really a hydroxyl chloride. Zirconium oxychloride is produced commercially by caustic fusion of zircon, followed by washing with water to remove sodium silicate and to hydrolyze the sodium zirconate; the wet filter pulp is dissolved in hot hydrochloric acid and is recovered from the solution by crystallization. An aqueous solution is also produced by the dissolution and hydrolysis of zirconium tetrachloride in water, or by the addition of hydrochloric acid to zirconium carbonate. Zirconium oxychloride is an important intermediate from which other zirconium chemicals are produced. It readily effloresces, and hydrates with 5-7 H2O are common. The salt cannot be dried to the anhydrous form and decomposes to hydrogen chloride and zirconium oxide. Applications include catalysis, special ceramics, pigments and filler coatings, cement and drilling muds,

ZIRCONIUM SILICATE SUPPLIERS TAM CERAMICS LLC 4511 Hyde Park Blvd. Niagara Falls, NY 14305 (716) 278-9403 Fax: (716) 278-9571 Email: [email protected] Website: www.tamceramics.net TREBOL Ave. Los Angeles No. 3408 Ote. Fracc. Coyoacan Monterrey, N.L. 64510 Mexico (52) 81-8126-2300; (52) 81-8126-2321 Fax: (52) 81-8126-2303 Email: [email protected] Website: www.gtrebol.com ZIRCONYL PHOSPHATE or ZIRCONIUM PHOSPHATE. Zirconium phosphate (Zr(HPO4)2-nH2O) can be used as a starting material for zirconium phosphate based ceramics such as NZP. Sodium zirconium phosphates (NZP) exhibit unique properties such as low thermal expansion and high thermal shock resistance. Zirconium phosphate is an ion exchange material and has been used to extract cesium from radioactive wastes. ZTA. Abbreviation for zirconia-toughened alumina. A composite consisting of an alumina matrix and a dispersion of partially-stabilized tetragonal zirconia.

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THE NEXT STAGE OF

COMPLIANCE by Malcolm Carroll, Director, Reach Delivery, Hemel Hempstead, Hertfordshire, UK

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EACH (Registration, Evaluation, Authorization and restriction of Chemicals) is the European Union (EU) regulation that focuses on the safe use and distribution of chemicals. The regulation came into force in June 2007 and is arguably one of the most complex and far-reaching pieces of legislation to impact chemical manufacturers, importers, distributors, and downstream users of chemicals worldwide. The regulations affect companies of all sizes—regardless of where they are based in the world—as REACH applies to any company that imports to or manufactures in the EU. To comply with REACH, organizations are now responsible for registering chemicals and ensuring the delivery of material safety data sheets (MSDS, now known simply as safety data sheets, or SDS) and associated documentation to their customers. Companies are also responsible for keeping these documents, and their customers, up to date in the event of any changes or clarifications. Failure to comply with these regulations will not only place a business at risk, it may jeopardize health and safety and waste all of the hard work that has gone into achieving REACH compliance.

Recent Developments According to Geert Dancet, executive director of the European Chemicals Agency (ECHA), the first phase of REACH compliance was completed successfully on November 30, 2010. This phase involved the registration of widely used chemicals, particularly those that are hazardous, with the ECHA. Beginning December 1, 2010, all unregistered manufacturers and importers of over 1000 tons/year were considered to be operating illegally. A year has passed and the industry has shifted its focus firmly to the next REACH landmark, which is 2013 REACH registration. At the European Commission’s REACH Registration Conference in September 2011, the “REACH 2013 – ACT Now!” campaign was launched by ECHA. Manufac90

January 2012 ³ WWW.CERAMICINDUSTRY.COM

³ Compliance with REACH regulation requires companies to have up-to-date information on chemical substances. turers, importers and downstream users of chemicals not yet complying with the REACH regulations were urged to start preparing now for the deadline of May 31, 2013, when all substances manufactured or imported in the EU above 100 metric tons a year must be registered under REACH. Organizations must also remain aware of the proposed new U.S. legislation, similar to REACH, that is under consideration for shipments into the U.S. market.

special section | resource management

SDS Delivery After registration, compliance involves the production and delivery of the new SDSs, which are needed at every stage of the supply chain. REACH requires big changes for EU chemical importers in the way they are required to deliver, receive and manage SDSs. In a highvolume industry that has constant pressure on margins, the new regulations present manufacturers, importers, aggregators and even retailers with a tough administrative challenge that could prove to be incredibly costly. What is already clear is that traditional methods of delivering documents are not accurate, cost-effective or robust enough to meet the REACH compliance standards. Each traditional method of delivering documents has shortcomings; for example: • Email does not guarantee or record proof of delivery without significant time, effort and cost; this type of delivery obviously does not physically replace old, outof date-versions of an SDS. • Regular mail has the same problems as emails, adding the additional costs and time associated with stationery, postage, and administration. • Placing documents onto a website will not suffice, as this provides no proactive delivery and is already rejected by REACH. In addition, these methods will not help with the intent of REACH. Customers will not be alerted to any changes in the SDSs, multiple recipients cannot be easily managed, and there are no standards in terms of the media on which the SDS is held—making easy and consistent access difficult. All of this could result in either significant additional costs for suppliers or the possibility of errors, leading to noncompliance with the regulations.

Possible Solutions As this next stage of REACH begins, the issues companies in the industry face are significant. How should companies fully comply with the legislation in respect of delivery and receipt of SDSs? How do they maintain their operations and ensure consistent use of current information across

all operational areas? How do they effectively audit internal and external delivery, receipt and access of critical information by customers? Most importantly, how do they address possible legal action should the need arise? REACH Delivery is a new industry-wide SDS delivery service that helps companies eradicate administration headaches concerning the delivery of SDSs and other documents. This secure online service enables the electronic delivery, receipt, control, update, audit and tracking of SDSs in line with REACH regulations. The service automates the entire SDS delivery process, including monitoring, tracking and reporting on all documents that are sent to customers. It retains a delivery status for documents sent and alerts users only when they need to follow up. Any document updates are automatically identified, and the new SDSs replace the previously sent versions. Customers and staff will receive alerts about the new SDS to ensure they are always up to date. Documents from all of a company’s suppliers are all stored in a single electronic database, providing users a single consistent point of access for the latest version of a SDS. Any documents that a user chooses to store locally on their PC are also automatically kept up to date, so it is possible to work on- or offline. The service is intended to be simple to access and operate, and charges are on a pay-asyou-use basis. REACH compliance is a hugely complex issue for companies that import or distribute substances. Automating and

guaranteeing the safe delivery of SDSs helps ease the complexity, reduce the costs, and improve health and safety within the industry. Companies have invested time and effort into getting the content of the SDS/ MSDS right. It is just as important to ensure they are delivering the documents in line with the new regulations to ensure that they remain in compliance with REACH legislation.  For more infor mation, v isit www. reachdelivery.com.

³ BUYERS’

CONNECTION

CERAMIC INDUSTRY ³ January 2012

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³ Exoskeletal technologies support the musculoskeletal system while allowing full spatial and rotational freedom of motion.

special section | resource management The X-Ar attaches to a human’s arm and becomes, in essence, a mechanical arm.

Safety

in Technology

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epetitive motion injuries are among today’s most common work-related ailments. What’s more, these injuries can be worsened by the repetitive actions used in our day-to-day lives. It is important for manufacturers to provide the appropriate setup and equipment to optimize worker health and prevent injury. Based in Los Angeles, Calif., Equipois is a four-year-old company whose goal is to make humans safer and more productive through the use of its exoskeleton technology, the X-Ar™. Eric Golden, president and CEO of Equipois, explains the technology and its benefits.

of time, the X-Ar simply attaches to a human’s arm and becomes, in essence, a mechanical arm, providing dynamic support throughout the user’s range of motion while significantly minimizing fatigue and discomfort. The X-Ar is the first technology that utilizes an exoskeleton to increase the human arm’s stamina and strength. We believe that the human hand guided by the human brain is the most powerful and versatile tool ever created. The X-Ar enhances that tool, rather than trying to mimic or replace it, and should significantly impact the workplace across diverse industries.

What is the X-Ar? The X-Ar exoskeletal arm support attaches to the human arm and can allow plant personnel, laboratory technicians, and others to work more safely and precisely. We expect future versions of the technology to be able to help disabled persons control their arms and legs, and improve the performance and safety of America’s armed forces.

How was X-Ar developed? The X-Ar is a descendent of our zeroG® mechanical arm technology, which holds tools and parts so operators can manipulate them as if weightless, but with practically unlimited freedom of motion. Originally developed with Garrett Brown, inventor of the Steadicam® camera stabilization system, the zeroG floats objects as if in zero gravity, with complete freedom of motion. The result is that workers can operate heavy tools or move objects with much less fatigue, allowing them to accomplish more with much less risk of injury.

How is it used? Designed to assist with a range of activities in industries where people work with their arms outstretched for long periods 92

January 2012 ³ WWW.CERAMICINDUSTRY.COM

What companies use the products? zeroG has been adopted by some of the world’s leading manufacturers in aerospace, automotive and other industries, including companies such as Boeing and Ford.  For more information, visit www.equipoisinc. com.

Eric Golden, Equipois president and CEO, demonstrates the X-Ar’s range of motion.

³ SERVICESMARKETPLACE ³CONSULTING & ENGINEERING SERVICES

³MAINTENANCE/SERVICES

Brinks Hofer Gilson & Lione . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

Ceramic Maintenance Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99

Ceralink, Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93 HED International . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

³PROCESSING SERVICES

Ragan Technologies, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

AVEKA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

Richard E. Mistler, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93

CCE Technologies, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

Ruark Engineering, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

Powder Processing and Technology, LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99

Semler Materials Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93

Powder Technology, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 TAM Ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

³CONTRACT MANUFACTURING SERVICES

Union Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

C-Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94 Coalition Technology Co., Ltd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95

³RECYCLING SERVICES

CoorsTek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

A-Ten-C, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

Superior Technical Ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

³REFRACTORY SERVICES ³FINISHING & MACHINING SERVICES

Fuse Tech/Hot Tech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

Advanced Ceramic Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 Bullen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95

³SPRAY DRYING

EBL Products, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95

General Spray Drying Service, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

Ferro-Ceramic Grinding, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96 Machined Ceramics, Inc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

³CONSULTING & ENGINEERING SERVICES

O’Keefe Ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 PremaTech Advanced Ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 Sonic-Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

³FIRING & DRYING SERVICES Allied Kiln Service Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 American Isostatic Presses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Centorr/Vacuum Industries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96 Harrop Industries, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96 HED International . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Ipsen Ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

Experts in Ceramic Engineering & Materials Science • Microwave & RF Process Development • Scale-up • Equipment Design

• Materials Engineering Ceramics, Glass, Composites

• Research and Innovation • Prototyping

518-283-7733 * Fax: 518-283-9134 * [email protected] * www.ceralink.com

I Squared R Element Co., Inc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96 SBL Kiln Services, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 TevTech, LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97

³GLASS SERVICES Ceradyne VIOX, Inc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 Fuse Tech/Hot Tech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Glass Inc. International . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 SEM-COM Co., Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Specialty Glass, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97

³INDEPENDENT AGENTS

Phone: 480-895-9830 FAX: 480-895-9831 e-Mail: [email protected]

Dr. Charles E. Semler President/Consultant SEMLER MATERIALS SERVICES 10153 E. Elmwood Dr. Chandler, AZ 85248

Tape Casting Warehouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 Taylor Tunnicliff Ltd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98

³LABORATORY & TESTING SERVICES Activation Laboratories Ltd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 Geller Microanalytical Laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 Harrop Industries, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 JTF Microscopy Services, LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 Micron Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 Netzsch Instruments NA LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 NSL Analytical Services Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 Quantachrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 West Penn, Spectrochemical Labs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99

CERAMIC INDUSTRY ³ January 2012

93

³CONSULTING & ENGINEERING SERVICES / CONTRACT MANUFACTURING SERVICES

High Shear Compaction— Superior Tape Forming Process

³CONTRACT MANUFACTURING SERVICES

• Full thickness single layer tapes: • HSC efficient high-volume 0.1 mm to greater than 13 mm process compatible with any powder: ceramic, glass, metal • Aqueous binder systems— extreme thickness control or plastic Ragan Technologies Inc. • Tape Development > Toll • Improvement over roll compac978-297-9805 Manufacturing > Turnkey tion —Isotropic tapes are [email protected] Installations never brittle & fire flat www.ragantech.com

Master Tapecaster Development Service Center Our new “state-of-the-art” tapecasting laboratory is designed for precision testing, development and contract toll casting services. If you want to make the best tapecast product on the planet...

CALL US TODAY: 1-800-433-5456 P. O. B ox 2 4 6 Ringoes, NJ 08551 Te l : 6 0 9 - 4 6 6 - 1 9 0 0 Fa x : 6 0 9 - 4 6 6 - 3 6 0 8 We b : www.hed .c o m E-ma il: info @hed .c o m

Michael S. Gzybowski Intellectual Property Attorney 734.302.6046 [email protected]

INNOVATIVE SOLUTIONS FROM CONCEPT TO PRODUCTION • • • •

Delivering solutions for diverse applications & industries Extrude, dry press, iso press, precision machine AS9100 & ISO9001:2008 Certified Plantwide Customer-Focused Culture

802-527-7726 • [email protected] • www.ceramics.net

Alumina • Zirconia • ZTA • Steatite • Cordierite • BN • Macor

Precision Ceramic Components fj^X`"ijgc egdidine^c\

Suite 200 | 524 South Main Street | Ann Arbor, MI 48104 usebrinks.com ]^\]"kdajbZ bVcj[VXijgZg

Ruark Engineering, Inc. Customer Oriented Expert Kiln Assistance • • • •

Ralph Ruark, PE 10506 Cypress Point Drive Bradenton, FL 34202

94

Veea^XVi^dc Zc\^cZZg^c\

CONTINUOUS IMPROVEMENT OF KILN OPERATIONS KILN UPGRADE AND MODIFICATIONS NEW KILN PROCUREMENT SPECIALIZED TRAINING ON SITE P: 941-730-2253 F: 941-360-3211 [email protected] http://www.ruarkengineering.com

January 2012 ³ WWW.CERAMICINDUSTRY.COM

CoorsTek is the largest US-owned technical ceramics manufacturer in the world. Call 303-271-7006 or email [email protected] for expert assistance on your next project. Visit us on the web www.coorstek.com

³CONTRACT MANUFACTURING SERVICES / FINISHING & MACHINING SERVICES ³CONTRACT MANUFACTURING SERVICES

³FINISHING & MACHINING SERVICES

WORLD LEADER IN PRECISION CERAMICS

Over a Quarter Century of Precision Ceramic Machining Process Development, has resulted in hundreds of satisfied customers. Put our experience and knowledge to work for you and become one of our satisfied customers.

719-687-0888 • [email protected] • www.okeefeceramics.com

³FINISHING & MACHINING SERVICES

28 Years of Precision Ceramic Grinding

EBL PRODUCTS, INC. PIEZOCERAMICS Serving our customers for over 50 years PRECISION CUSTOM DESIGN for:

• • • •

piezoceramic tubes piezo composites lead zirconate titanates matching layers & wearplates

EBL Products, Inc. 22 Prestige Park Circle, E Hartford CT 06108 Phone: 860-291-2537 • Fax: 860-291-2533 www.eblproducts.com [email protected]

in d n

i Gr & i on Machining fC era ls m eria

Pre o cis

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• Custom forming of technical ceramics * Built to customer print * • Prototype, short run and high volume production quantities • Multiple C.N.C. Capabilities Phone: 714-538-2524 Fax: 714-538-2589 Email: [email protected] Website: www.advancedceramictech.com

YOUR OU U ULTRASOURCE SOU C FOR MACHINING HARD & BRITTLE MATERIALS

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PremaTech Advanced Ceramics is a highly respected, world leader in advanced custom machining and grinding for the Semiconductor, Aerospace & Defense, Research, Life Sciences and Commercial industries. For all your ceramic needs, please call 508.791.9549 NEW Lapping & Polishing Capabilities

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Advanced Ceramic Machining & Components Engineering and Design Support Grinding of Hard and Ultrahard Materials: Alumina, Boron Nitride, Ferrite, Quartz, Silicon Carbide, Silicon Nitrides and Zirconia

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1301 Miller Williams Rd. Eaton, Ohio 54320 USA Phone: (937) 456-7133 • Fax: (937) 456-2779 Email: [email protected] CERAMIC INDUSTRY ³ January 2012

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Contract Machining Company and Ceramic Component Supplier • ISO 9001:2000 & AS9100B • CAD/CAM CNC Machining • Extensive Material Inventory • Material/Technical Support • Over 40 Years of Service

SERVICES

Specializing in BN, SiC, Macor, Si N , Al O , ZrO , Quartz, Ferrites and other related materials 3

4

TOLL FIRING

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2

• Sintering, calcining, heat treating to 1700°C • Bulk materials and shapes • R&D, pilot production • One-time or ongoing EQUIPMENT

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TOLL FIRING and CERAMIC REFRACTORIES

• Multiple kilns and furnaces for optimal firing options • Screening, surface area, and bulk density testing available • Custom and standard ceramic refractories • Alumina and Fused Silica formulas • Shapes include saggers, tiles, crucibles, kiln furniture [email protected] • (815)239-2385 ext. 105 www.ipsenceramics.com

I SQUARED R ELEMENT CO., INC. AKRON, NY USA

• Custom Designed Silicon Carbide & Molybdenum Disilicide Heating Elements for Your Application • Engineering Assistance & Trouble Shooting • Customized Accessories

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January 2012 ³ WWW.CERAMICINDUSTRY.COM

TOP GUN HIGH FIRE KILN

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ISOSTATIC PRESSING Specializing in

HIP, CIP, Service and Equipment Visit us on the Web: www.aiphip.com Call toll free: 800-375-7108

American Isostatic Presses 1205 S. Columbus Airport Rd. Columbus, Ohio 43207 Phone (614) 497-3148 Fax (614) 497-3407

TEVTECH, LLC MATERIALS PROCESSING SOLUTIONS Custom Vacuum Furnaces & Hot Zone Refurbishment for Sintering • CVD • Purification • Brazing

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CALL US TODAY: 1-800-433-5456 UNIQUE/PERENY KILNS AND FURNACES • PRO-CAST TAPECASTING SYSTEMS

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PRESIDENT

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INCORPORATED INTERNATIONAL 14055 LAURELWOOD PL • CHINO, CA 91710 email: [email protected] website: www.glassint.com Phone 909-628-4212

SEM•COM

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COMPANY, INC.

SPECIALTY & ELECTRONIC GLASS MANUFACTURING We provide the following services:

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Refractory Repair Specialists • Ceramic Welding & Periscope Surveys • Port & Checker Cleaning • Hot Refractory Sawing & Drilling • Furnace Overcoating • Hot & Cold Refractory Repair

CERAMIC INDUSTRY ³ January 2012

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³GLASS SERVICES / INDEPENDENT AGENTS / LABORATORY & TESTING SERVICES ³LABORATORY & TESTING SERVICES

Electronic and Specialty Glass Frits & Powders • • • • • • • • • •

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Experiennced analysis of Adva Experienced Advanced anceed cceramic erramicc m materials atterialss in including ncluudi ding alumina, magnesia, zirconia, carbides, nitrides, and oxides. Specialized Testing Capabilities Compositional Analysis Elemental and Chemical Analysis Microscopy and SEM Thermal Analysis

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Trace Level Analysis Bulk Composition Thermal Conductivity Contaminants Inclusions Failure Analysis

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Trust

|

Technology

|

Turnaround

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SERVICESMARKETPLACE

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Powder and Porous Materials Characterization Laser diffraction particle size BET surface area Density DVS www.labqmc.quantachrome.com [email protected] 1-800-989-2476

• Ball & Pebble Mill Parts • Field Service & Installation • Thickness Testing • Mill Doors & Gaskets

ic Ceram

Maintenance Services, I

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n c.

Providing Quality Service for Over 25 Years

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³PROCESSING SERVICES

Your Source for Powder Processing

JTF Microscopy Services, LLC Microscopy, Petrographic Analysis, Training & Consulting • Glass defect analysis and source identification • Furnace refractory failure investigations • Glass technology support services related to glass defect issues • Training seminars – on-site, on your own equipment

• Raw material contaminant identification • Trouble-shooting and correction of microscope equipment problems • Consulting for equipment purchases: microscope, camera & sample preparation • Expert witness services in legal actions

phone: 607.292.6808 • mobile: 607.731.8863 email: [email protected] • website: www.jtfmicroscopy.com

We specialize in: • Spray Drying • Wet and Dry Milling • Calcining and Sintering Typical Applications: • Catalysts • Electronics • Ceramics • Fuel Cells For more information, please contact Alan Sukovich at 219-462-4141 x224 or [email protected] 5103 Evans Avenue | Valparaiso, IN 46383

www.pptechnology.com

! e r e h d a r u o y e plac

CONTACT Amy Vallance @ 281-550-5855 or [email protected] to place yours today.

CERAMIC INDUSTRY ³ January 2012

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³PROCESSING SERVICES

! e r e h d a r u o y place

CONTACT Amy Vallance @ 281-550-5855 or [email protected] to place yours today.

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LOWER COST MILLING SOLUTIONS Holding off on capital purchases? Union Process still has several low cost options for you to get the job done economically and efficiently using the finest size reduction equipment on the market.

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TOLL MILLING

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Save on capital equipment, personnel and space. Let Union Process toll grind your product in our Pilot Plant.

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REBUILDING Got a used Attritor in need of an update? Talk to Union Process about our 8-step refurbishing process using all OEM parts.

"EFORE !FTER

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8SPP*VII ENGINEERED PARTICLES Custom Particle Processing featuring:

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[email protected] ISO 9001: 2008 Registered 2045 Wooddale Drive Woodbury, MN 55125 For more information visit: www.aveka.com 651-730-1729 | FAX 651-730-1826 or Call Toll Free: 1-888-317-3700

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* Advanced Material Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71 [email protected]

Netzsch Instruments NA LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 www.netzsch-thermal-analysis.com

* American Chemet Corp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 www.chemet.com

* Prince Minerals, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78 www.princeminerals.com

* C-E Minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69 www.ceminerals.com

* Saint-Gobain Ceramics Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 www.refractories.saint-gobain.com

* Ceradyne, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73 www.ceradyne.com

St. Louis Section Refractory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 [email protected]

* Ceradyne VIOX, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 www.viox.com

Superior Graphite Co. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72 www.superiorgraphite.com

Ceramic Color & Chemical Mfg. Co.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 www.ceramiccolor.com

TAM Ceramics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86 www.tamceramics.com

Ceramic Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 www.ceramicindustry.com

* Tokuyama America Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 [email protected]

* FLSmidth Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 www.flsmidth.com

Tri-Mer Corp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91 www.tri-mer.com

H.C. Starck GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 www.hcstark.com

U.S. Silica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68 www.u-s-silica.com

* Harrop Industries Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 [email protected]

* UK Abrasives, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 www.ukabrasives.com

Imerys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 www.imerys-ceramics.com

* Unimin Corp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 [email protected]

* LignoTech USA Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 www.lignotech.com

Union Process Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 www.unionprocess.com

* Mason Color Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 www.masoncolor.com * See our ad in the 2011-2012 Ceramic Industry Data Book & Buyers’ Guide. This index is a feature maintained for the convenience of the advertiser. It is not part of the advertiser’s contract, and Ceramic Industry assumes no responsibility for its accuracy.

102

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