Structural Ceramics PDF
Preview Structural Ceramics
TREATISE EDITOR HERBERT HERMAN Department of Materials Science and Engineering State University of New York at Stony Brook Stony Brook, New York ADVISORY BOARD Μ. E. FINE G. KOSTORZ Department of Materials Science Institut fur Angewandte Physik Northwestern University ETH-Honggerberg Evanston, Illinois Zurich, Switzerland A. N. GOLAND J. B. WACHTMAN, Jr. Department of Physics Center for Ceramics Research Brookhaven National Laboratories Rutgers University Upton, New York Busch Campus Piscataway, New Jersey P. B. HIRSCH, FRS Metallurgy and Metal Science Depz Oxford University Oxford, England STRUCTURAL CERAMICS EDITED BY JOHN B. WACHTMAN, JR. Center for Ceramics Research Rutgers University Busch Campus Piscataway, New Jersey TREATISE ON MATERIALS SCIENCE AND TECHNOLOGY VOLUME 29 ACADEMIC PRESS, INC. Harcourt Brace Jovanovich, Publishers Boston San Diego New York Berkeley London Sydney Tokyo Toronto Copyright © 1989 by Academic Press, Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. ACADEMIC PRESS, INC. 1250 Sixth Avenue, San Diego, CA 92101 United Kingdom Edition published by ACADEMIC PRESS INC. (LONDON) LTD. 24-28 Oval Road, London NW1 7DX Library of Congress Cataloging-in-Publication Data Structural ceramics. (Treatise on materials science and technology; v. 29) Bibliography: p. Includes index. 1. Ceramic materials. I. Wachtman, J. B., Date - II. Series. TA403.T74 vol. 29 [TA430] 620.1Ί s 87-35160 ISBN 0-12-341829-1 [620.Γ4] Printed in the United States of America 89 90 91 92 9 8 7 6 5 4 3 2 1 Contributors Numbers in parentheses indicate the pages on which the authors' contributions begin. DONALD H. BUCKLEY (293), Case Western Reserve University, Cleveland, Ohio W. ROGER CANNON (195), The Center for Ceramics Research, N.J. Com mission on Science and Technology Center, Brett and Bowser Roads, Busch Campus, PO Box 909, Piscataway, New Jersey 08854 DALE L. HARTSOCK (27), Ford Motor Company, PO Box 2053, Dearborn, Michigan 48121-2053 R. NATHAN KATZ (1), Ceramics Research Division, Army Materials and Mechanics Research Center, Watertown, Massachusetts 02172 RICHARD L. LEHMAN (229), Rutgers State University, The Center for Ceramics Research, Brett and Bowser Roads, Busch Campus, PO Box 909, Piscataway, New Jersey 08854 ARTHUR F. MCLEAN (27), Ceramic Materials Department, Ford Motor Company, PO Box 2053, Dearborn, Michigan 48121-2053 KAZUHISA MIYOSHI (293), National Aeronautics and Space Administration, Lewis Research Center, Cleveland, Ohio 44135 M. SRINIVASAN (99), Materials Characterization and Properties Research, Niagara Falls R&D Center, PO Box 832, Niagara Falls, New York 14302 MAURICE L. TORTI (161), Norton Company, High Performance Ceramics, Goddard Road, Northboro, Massachusetts 01532-1545 IX Preface Structural ceramics is an emerging class of engineering materials with a variety of current applications and with the potential for much wider application, especially at high temperatures. High-performance structural ceramics uniquely combine strength, strength retention at high temperatures, hardness, dimensional stability, good corrosion and erosion behavior, high elastic modulus, and low mass density. Structural ceramics are used as monolithic parts, as composites, and as protective coatings. Monolithic structural ceramics are currently based primarily on silicon carbide, silicon nitride, partially stabilized zirconium dioxide, or alumina. Ceramic matrices combined with particulates, whiskers, or fibers of a different ceramic compound or a metal for enhanced performance have yielded composites with several times the toughness of monolithic ceramics. Use of structural ceramics to carry high tensile stresses in engineering applications requires care. The failure mode is typically sudden and complete. There is a distribution of strengths and consequently a continuously decreas ing probability of failure as stress is lowered rather than a single, well-defined strength. Consequently, a special discipline of design with brittle materials is needed and good quality control is essential. A large body of information on structural ceramics exists in many journals and in conference proceedings, some of which are difficult to obtain. The present book attempts to present an overview of this field. The level is technical but the treatment is addressed to the engineer or scientist who may not be an expert in this field. It is hoped that the book can serve as an reference book for experts as well as an introduction for technical persons in other disciplines. Each ceramic, such as silicon carbide, is not a single material but a family of materials with widely different sets of properties. Within the silicon carbide family the set of properties associated with say, reaction bonded silicon carbide may be best for one application while for another application hot pressed silicon carbide may be best. The same situation exists for the other major families of structural ceramics. Thus a xi xii PREFACE large set of options exists and considerable detailed knowledge is needed to make an optimum choice. The chapters in this book on each family of structural ceramics therefore treat the most important types within each family and present typical property data for each. The treatment begins with a survey by R. Nathan Katz of present uses and potential uses. The main types of structural ceramics are presented and both opportunities for their use and barriers are discussed. Arthur F. McLean and Dale L. Hartsock then provide a treatment of design with structural ceramics. The next three chapters provide detailed surveys of the silicon carbide family by M. Srinivasan, the silicon nitride and sialon family by Maurice L. Torti, and transformation toughened ceramics by W. Roger Cannon. Achievement of good properties with high reliability and at reasonable cost in actual parts is dependent on good processing. For each family of structural ceramics the various processing routes are treated. Any one of these families of materials can be given special and usually improved properties by reinforcing them with whiskers or fibers of other ceramics. This subject is treated in a cross-cutting overview by Richard L. Lehman. Many applications for structural ceramics in heat engines and other machinery involve moving parts which must often resist wear or erosion. The tribology of structural ceramics is treated in another cross-cutting chapter by Donald H. Buckley and Kazuhisa Miyoshi. John B. Wachtman, Jr. 1988 TREATISE ON MATERIALS SCIENCE AND TECHNOLOGY, VOL. 29 1 Opportunities and Prospects for the Application of Structural Ceramics R. NATHAN KATZ Army Materials Technology Laboratory Watertown, MA I. Introduction 1 II. Ceramics in Heat Engines 4 A. Ceramics for Diesel-Engine Applications 5 B. Application of Ceramics in Gas Turbines 10 III. Bearings 15 IV. Ceramics for Metal Shaping 17 V. Industrial Wear Parts 18 VI. Bioceramics 20 VII. Military Ceramics 21 VIII. Implications of High-Performance Structural Ceramics 23 References 25 I. Introduction Modern high-performance ceramics are the "enabling" materials for many advanced technologies. Electronics, telecommunications, optical systems, sensors, catalysts, bone replacements, heat exchangers, heat engines, and metal-shaping equipment are all either benefiting from or projected to benefit from advanced ceramic materials. This chapter will focus on the applications for high-performance structural ceramics—materials that combine the tradi tional advantages of ceramics (chemical inertness, high-temperature capabili ty, and hardness) with the ability to carry a significant tensile stress. The payoff to society from the utilization of structural ceramics is potentially large. Table I lists some of the performance benefits that have been demonstrated to be attainable for typical applications. The fuel savings from the adiabatic diesel engine are projected to be as large as $5 billion in the United States alone (Katz 1980). Additionally, the utilization of relatively ι Copyright © 1989 by Academic Press, Inc. All rights of reproduction in any form reserved. ISBN 0-12-341829-1 2 R. NATHAN KATZ TABLE I PAYOFF OF STRUCTURAL CERAMICS IN SELECTED APPLICATIONS Application Payoff Materials Light-duty Diesel 10-15% reduction in Zirconias, silicon nitrides, (uncooled) specific fuel consumption silicon carbides, aluminas, aluminum titinates Heavy-duty diesel 22 % reduction in specific Zirconias, silicon nitrides, (adiabatic) fuel consumption silicon carbides, aluminas, aluminum titinates Light-duty automotive gas 27 % reduction in specific Silicon nitrides, silicon turbine fuel consumption carbides, LAS, MAS Recuperator for slot forging 42 % reduction in fuel Silicon carbides furnace consumption Machining of grey cast iron 220% increase in Silicon nitrides (& SiAlON's) productivity Extrusion dies for brass 200 + % increase in Zirconias productivity abundant ceramics offers the promise of a reduced dependence on imported critical metals. The bulk of the high-performance ceramics under development today are based on silicon nitride, silicon carbide, zirconia, or alumina. Typical properties of these classes of materials are shown in Table II, where the ceramic properties are also compared to the properties of conventional engineering metals. Details of the variation in properties available within each family of structual ceramics and how they derive from variations in processing methodology and chemistry will be discussed in Chapters 3,4, and 5. What is important to note here is that one can specifically tailor a wide range of properties from each of these families of advanced ceramics in order to optimize materials performance for the application at hand. Of equal importance to the development of the high-performance struc tural ceramic materials themselves has been the emergence of brittle- materials design technology. Brittle-materials design is a new and rapidly developing science-based engineering art that is critically dependant on modern computer technology. This key area is discussed by McLean and Hartsock in chapter 20. Thus, today we have greatly improved capacities both in the design of and design with modern ceramics. Structural ceramics come in many forms: monolithic ceramics, ceramic composites, ceramic coatings, and ceramic fibers and whiskers. Most struc tural ceramics in production today are monolithic. However, much work is currently focused on ceramic matrix composites (fiber, whisker, or particu late), mainly with a view to increasing the fracture toughness and/or strain to χο χο jl^p „ ^ ^h o^^o c ^ ^h ozio ο ο « ι^ θ Β ) ^ 5( « ο « ),Λ 8ο fcgB + ϋ Jl 3 » 13 & ! i Si (Ν *-* ^ οο ^inr . iO-H *0-0h (N^ ε 2 8 2 b S 9Β2έ 82 b ε ^3< u -ο Ο υ 3^ δ 023 H 5δ (2Η - H g ο 2 •Ο ° m Ο ω Λ Ο υ +-» ν; ^ ο 2 8. Λ -a & ε 8 a γο Ο Ο w ε oo Ζ So δ ΟO N 8 s ^ <Λ Ο o«n c«oo Ο £ <υ ι ^ ^ ο cd Ο so 1 s 8 "a Ο 8 g 8 ?S ? o 2 ο "α2> on 21-r3 cn T"L, £Ο(Ν 02ws u-> Cw Μco Cw 0uC0OoI ^W4ω3) 3 «uΟ/oιo ·<-υΛ ooι <u^ CN C Ο C Ό G υ 00 0D0 Ο ε ο W5 r,i .5 W Ο ed c3 Ν (J < rj '"a cd > U 4 R. NATHAN KATZ failure of structural ceramics. This area is reviewed in depth by Lehman in chapter 6. Ceramic coatings are not normally thought of as load-bearing. However, Zr0- or Cr0-based coatings used in cylinder liners of diesel 2 2 3 engines are subjected to pressure and thermal cycling, as well as sliding wear with attendant point loads. (A more detailed discussion of this point will be found in Chapter 7.) Ceramic fibers such as A10 and mullite are currently 2 3 finding a market as reinforcements in metal matrix composites. A typical application is a ceramic fiber-reinforced piston ring groove for diesel pistons. The increased temperature and pressure that the ceramic fiber reinforcement allows has yielded measurable engine-performance gains. Notwithstanding the benefits of ceramic matrix composites, coatings, and fibers in selected structural applications, this chapter will focus on the opportunities and prospects for the application of monolithic structural ceramics, as this is where the bulk of the markets and applications are likely to be through the start of the twenty-first century. Following this brief introduction we shall now examine several areas of current and future structural applications of ceramics. In each case, we shall examine what benefits ceramics offer the designer seeking enhanced systems performance, which ceramics may provide the desired capability, and the current status and future prospects for ceramics in the application. The major applications areas to be covered are heat engines, bearings, metal working, industrial wear components, bioceramics, and military applications. The implications of high-performance structural ceramics to the industrial econo my of the twenty-first century will also be discussed. II. Ceramics in Heat Engines As indicated in Table I, the utilization of ceramics in heat engines can facilitate major reductions in fuel consumption of gas turbines and diesel engines. Ceramics can also play a role in increasing the performance of vehicles with conventional gasoline-fueled spark-ignited engines. The role of ceramic components in increasing the performance of each of these engine classes is different and, thus, different materials properties are utilized. Increased performance and decreased specific fuel consumption (SFC or pounds of fuel burned per horsepower hour) in the case of the gas turbine result directly from the ability of the ceramic to work at higher temperatures than superalloys and to do so without cooling. Thus, ceramics enable both a more efficient thermodynamic cycle and the elimination of parasitic mechani cal losses due to the pumping of cooling air as required in advanced metallic gas turbines. The prime selection criteria for gas turbine ceramics are high- temperature strength, thermal shock resistance, and long-term durability.
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