Advanced Structural Ceramics E-Book

Bikramjit Basu

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 749

Veröffentlichungsjahr: 2011

Beschreibung

This book covers the area of advanced ceramic composites broadly, providing important introductory chapters to fundamentals, processing, and applications of advanced ceramic composites. Within each section, specific topics covered highlight the state of the art research within one of the above sections. The organization of the book is designed to provide easy understanding by students as well as professionals interested in advanced ceramic composites. The various sections discuss fundamentals of nature and characteristics of ceramics, processing of ceramics, processing and properties of toughened ceramics, high temperature ceramics, nanoceramics and nanoceramic composites, and bioceramics and biocomposites.

Leseprobe

Table of Contents

Cover

Title page

Copyright page

Dedication

Preface

Foreword

About the Authors

Section One: Fundamentals of Nature and Characteristics of Ceramics

Chapter 1 Ceramics: Definition and Characteristics

1.1 MATERIALS CLASSIFICATION

1.2 HISTORICAL PERSPECTIVE; DEFINITION AND CLASSIFICATION OF CERAMICS

1.3 PROPERTIES OF STRUCTURAL CERAMICS

1.4 APPLICATIONS OF STRUCTURAL CERAMICS

Chapter 2 Bonding, Structure, and Physical Properties

2.1 PRIMARY BONDING

2.2 STRUCTURE

2.3 OXIDE CERAMICS

2.4 NON-OXIDE CERAMICS

Chapter 3 Mechanical Behavior of Ceramics

3.1 THEORY OF BRITTLE FRACTURE

3.2 CRACKING IN BRITTLE MATERIALS

3.3 STRENGTH VARIABILITY OF CERAMICS

3.4 PHYSICS OF THE FRACTURE OF BRITTLE SOLIDS

3.5 BASIC MECHANICAL PROPERTIES

3.6 TOUGHENING MECHANISMS

Section Two: Processing of Ceramics

Chapter 4 Synthesis of High-Purity Ceramic Powders

4.1 SYNTHESIS OF ZrO2 POWDERS

4.2 SYNTHESIS OF TiB2 POWDERS

4.3 SYNTHESIS OF HYDROXYAPATITE POWDERS

4.4 SYNTHESIS OF HIGH-PURITY TUNGSTEN CARBIDE POWDERS

Chapter 5 Sintering of Ceramics

5.1 INTRODUCTION

5.2 CLASSIFICATION

5.3 THERMODYNAMIC DRIVING FORCE

5.4 SOLID-STATE SINTERING

5.5 COMPETITION BETWEEN DENSIFICATION AND GRAIN GROWTH

5.6 LIQUID-PHASE SINTERING

5.7 IMPORTANT FACTORS INFLUENCING THE SINTERING PROCESS

5.8 POWDER METALLURGICAL PROCESSES

Chapter 6 Thermomechanical Sintering Methods

6.1 HOT PRESSING

6.2 EXTRUSION

6.3 HOT ISOSTATIC PRESSING

6.4 HOT ROLLING

6.5 SINTER FORGING

6.6 SPARK PLASMA SINTERING

Section Three: Surface Coatings

Chapter 7 Environment and Engineering of Ceramic Materials

7.1 ENVIRONMENTAL INFLUENCE ON PROPERTIES OF ENGINEERING CERAMICS

7.2 CLASSIFICATION AND ENGINEERING OF CERAMIC MATERIALS

Chapter 8 Thermal Spraying of Ceramics

8.1 MECHANISM OF THERMAL SPRAYING

8.2 CLASSIFICATION OF THERMAL SPRAYING

8.3 SPLAT FORMATION AND SPREAD

8.4 NEAR NET SHAPE FORMING

8.5 OVERVIEW

Chapter 9 Coatings and Protection of Structural Ceramics

9.1 COATINGS

9.2 PROTECTIVE COATINGS

9.3 ROCKET NOZZLE INSERTS

9.4 THERMAL BARRIER COATINGS

9.5 WEAR RESISTANCE

9.6 CORROSION PROTECTION BY CERAMICS

9.7 OPTICALLY TRANSPARENT CERAMICS

9.8 CERAMIC POTTERY AND SCULPTURES

Section Four: Processing and Properties of Toughened Ceramics

Chapter 10 Toughness Optimization in Zirconia-Based Ceramics

10.1 INTRODUCTION

10.2 TRANSFORMATION CHARACTERISTICS OF TETRAGONAL ZIRCONIA

10.3 PHASE EQUILIBRIA AND MICROSTRUCTURE

10.4 TRANSFORMATION TOUGHENING

10.5 STABILIZATION OF TETRAGONAL ZIRCONIA

10.6 PRODUCTION AND PROPERTIES OF Y-TZP CERAMICS

10.7 DIFFERENT FACTORS INFLUENCING TRANSFORMATION TOUGHENING

10.8 ADDITIONAL TOUGHENING MECHANISMS

10.9 COUPLED TOUGHENING RESPONSE

10.10 TOUGHNESS OPTIMIZATION IN Y-TZP-BASED COMPOSITES

10.11 OUTLOOK

Chapter 11 S-Phase SiAlON Ceramics: Microstructure and Properties

11.1 INTRODUCTION

11.2 MATERIALS PROCESSING AND PROPERTY MEASUREMENTS

11.3 MICROSTRUCTURAL DEVELOPMENT

11.4 MECHANICAL PROPERTIES

11.5 CONCLUDING REMARKS

Chapter 12 Toughness and Tribological Properties of MAX Phases

12.1 EMERGENCE OF MAX PHASES

12.2 CLASSIFICATION OF MAX PHASES

12.3 DAMAGE TOLERANCE OF MAX PHASES

12.4 WEAR OF Ti3SiC2 MAX PHASE

12.5 CONCLUDING REMARKS

Section Five: High-Temperature Ceramics

Chapter 13 Overview: High-Temperature Ceramics

13.1 INTRODUCTION

13.2 PHASE DIAGRAM AND CRYSTAL STRUCTURE

13.3 PROCESSING, MICROSTRUCTURE, AND PROPERTIES OF BULK TiB2

13.4 USE OF METALLIC SINTER-ADDITIVES ON DENSIFICATION AND PROPERTIES

13.5 INFLUENCE OF NONMETALLIC ADDITIVES ON DENSIFICATION AND PROPERTIES

13.6 IMPORTANT APPLICATIONS OF BULK TiB2-BASED MATERIALS

13.7 CONCLUDING REMARKS

Chapter 14 Processing and Properties of TiB2 and ZrB2 with Sinter-Additives

14.1 INTRODUCTION

14.2 MATERIALS PROCESSING

14.3 TiB2–MoSi2 SYSTEM

14.4 TiB2–TiSi2 SYSTEM

14.5 ZrB2–SiC–TiSi2 COMPOSITES

14.6 CONCLUDING REMARKS

Chapter 15 High-Temperature Mechanical and Oxidation Properties

15.1 INTRODUCTION

15.2 HIGH-TEMPERATURE PROPERTY MEASUREMENTS

15.3 HIGH-TEMPERATURE MECHANICAL PROPERTIES

15.4 OXIDATION BEHAVIOR OF TiB2–MoSi2

15.5 OXIDATION BEHAVIOR OF TiB2–TiSi2

15.6 CONCLUDING REMARKS

Section Six: Nanoceramic Composites

Chapter 16 Overview: Relevance, Characteristics, and Applications of Nanostructured Ceramics

16.1 INTRODUCTION

16.2 PROBLEMS ASSOCIATED WITH SYNTHESIS OF NANOSIZED POWDERS

16.3 CHALLENGES FACED DURING PROCESSING

16.4 PROCESSING OF BULK NANOCRYSTALLINE CERAMICS

16.5 MECHANICAL PROPERTIES OF BULK CERAMIC NANOMATERIALS

16.6 APPLICATIONS OF NANOCERAMICS

16.7 CONCLUSION AND OUTLOOK

Chapter 17 Oxide Nanoceramic Composites

17.1 OVERVIEW

17.2 Al2O3-BASED NANOCOMPOSITES

17.3 ZrO2-BASED NANOCOMPOSITES

17.4 CASE STUDY

Chapter 18 Microstructure Development and Properties of Non-Oxide Ceramic Nanocomposites

18.1 NANOCOMPOSITES BASED ON Si3N4

18.2 OTHER ADVANCED NANOCOMPOSITES

18.3 WC-BASED NANOCOMPOSITES

Section Seven: Bioceramics and Biocomposites

Chapter 19 Overview: Introduction to Biomaterials

19.1 INTRODUCTION

19.2 HARD TISSUES

19.3 SOME USEFUL DEFINITIONS AND THEIR IMPLICATIONS

19.4 CELL–MATERIAL INTERACTION

19.5 BACTERIAL INFECTION AND BIOFILM FORMATION

19.6 DIFFERENT FACTORS INFLUENCING BACTERIAL ADHESION

19.7 EXPERIMENTAL EVALUATION OF BIOCOMPATIBILITY

19.8 OVERVIEW OF PROPERTIES OF SOME BIOMATERIALS

19.9 OUTLOOK

Chapter 20 Calcium Phosphate-Based Bioceramic Composites

20.1 INTRODUCTION

20.2 BIOINERT CERAMICS

20.3 CALCIUM PHOSPHATE-BASED BIOMATERIALS

20.4 CALCIUM PHOSPHATE–MULLITE COMPOSITES

20.5 HYDROXYAPATITE–Ti SYSTEM

20.6 ENHANCEMENT OF ANTIMICROBIAL PROPERTIES OF HYDROXYAPATITE

Chapter 21 Tribological Properties of Ceramic Biocomposites

21.1 INTRODUCTION

21.2 TRIBOLOGY OF CERAMIC BIOCOMPOSITES

21.3 TRIBOLOGICAL PROPERTIES OF MULLITE-REINFORCED HYDROXYAPATITE

21.4 TRIBOLOGICAL PROPERTIES OF PLASMA-SPRAYED HYDROXYAPATITE REINFORCED WITH CARBON NANOTUBES

21.5 LASER SURFACE TREATMENT OF CALCIUM PHOSPHATE BIOCOMPOSITES

Index

Copyright © 2011 by The American Ceramic Society. All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey.

Published simultaneously in Canada.

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Library of Congress Cataloging-in-Publication Data:

Basu, Bikramjit.

 Advanced Structural Ceramics / Prof. Bikramjit Basu, Dept. of Materials Science and Engineering, Indian Institute of Technology Kanpur, India, & Prof. Kantesh Balani, Dept. of Materials Science and Engineering, Indian Institute of Technology Kanpur, India.

pages cm

 Includes index.

 ISBN 978-0-470-49711-1 (cloth)

1. Ceramic materials. 2. Ceramic-matrix composites. I. Balani, Kantesh. II. Title.

 TA455.C43B375 2011

 620.1'4–dc22

2010048280

oBook ISBN: 978-1-118-03730-0

ePDF ISBN: 978-1-118-03728-7

ePub ISBN: 978-1-118-03729-4

Bikramjit Basu dedicates this book with a great sense of gratitude to his uncle,

Mr. Ranjit Mazumdar

Kantesh Balani dedicates this book to his father,

the late Mr. Parmanand B. Balani

Preface

The field of advanced structural ceramics is widely recognized as an increasingly important area for material scientists, space technologists, mechanical engineers and tribologists, biotechnologists, chemists, and medical professionals. Recent developments in our understanding of fundamental concepts of materials science have enabled impressive progress in the attempts to develop smart and tough structural ceramics. The progress in advanced structural ceramics clearly requires an improved understanding in multiple disciplines as well as the development of new design methodologies in order to obtain better properties in terms of physical, tribological, high-temperature, and even biological performance. From this perspective, this book has been structured into various theme sections, each of which contains a number of chapters. The first section of this book has been designed to facilitate readers who do not have a background in the area of structural ceramics processing and properties. While conceiving the contents of this book, the authors desired to motivate students and young researchers as well as to provide experts in the field with a healthy balance of topics for teaching and academic pursuits. It is expected that this book, if used as a text, would strongly benefit senior undergraduate and postgraduate students.

This unique book illustrates some recent examples of the development of new ceramic compositions or ceramics with refined microstructure and properties for various engineering applications, while covering requisite fundamentals necessary to understand the progress being made in ceramics science. This book aptly describes the fundamentals of mechanical properties and processing, while highlighting some of the recent advances in processing tools for fabricating ceramic-based bulk and coating materials. Further, the authors strongly consider the importance of tough ceramics (MAX phases, zirconia [ZrO2], and SiAlON-based ceramics) engineered for structural applications. The use of advanced ceramics as coatings for high-temperature applications is also well addressed. Additionally, this book deals pertinently with the newly enticing area of nanoceramic composites and biomaterials. An important feature of this book is that two sections review and refresh the reader’s familiarity with the fundamentals of the structure–property correlation as well as basic aspects of processing; subsequent sections covering theme areas also start with an overview chapter for easier understanding of the entire contents of the book. Each theme area also covers the most important ceramic systems.

In Section I, on the fundamentals, general properties of various engineering materials are discussed with particular reference to the distinguishable properties of ceramics. Various broad classifications of ceramics are also presented. The bird’s-eye view of their temporal growth, applications, and properties is also touched upon. The basic aspects of atomic bonding, structure, and physical properties, and their applications, are discussed in this section. The development of material properties resulting from the fundamental bonding and structure is also elucidated in this section. An important aspect of this section is the science-based discussion on the origin of brittle fracture and strength variability of ceramics. The concept of fracture toughness and measurement of various mechanical properties as well as a brief discussion on toughening mechanisms are also presented in this section.

Section II covers the (1) synthesis of high purity powders, which serve as the starting block for consequent sintering and shaping into useful products, (2) sintering mechanism, which is detailed with conventional sintering methods, and (3) emergence of advanced sintering techniques (i.e., thermomechanical processing), utilizing pressure in addition to temperature for processing ceramics. The synthesis of ZrO2, titanium diboride (TiB2), hydroxyapatite (HAp), and tungsten carbide (WC) powders is described to illustrate how some of the important technologically relevant powders can be synthesized.

Section III constitutes the environment and engineering of ceramic materials, associated with the damage that might result upon interaction. Hence, surface coatings become an essential component of applying ceramics for protection of surfaces exposed to high temperature, corrosion, wear, oxidation, and so on. Major thermal spraying techniques, such as plasma spraying, high-velocity oxy-fuel (HVOF), detonation-gun (D-gun), and electric arc, are described in this section. Thereupon, the role of coatings in material protection or functionality (such as in body implants), ultra-high-temperature wear resistance, thermal barriers, and so on, is represented.

A major drawback of ceramics is their highly brittle nature, which becomes a key parameter when developing structural components. Hence, Section IV concentrates on a special class of advanced tough ceramics, such as ZrO2-based ceramics, S-SiAlON ceramics, and the MAX phases. Toughness optimization via microstructural tailoring and controlling the processing conditions to achieve optimal performance of structural ceramics is presented herein.

Section V emerges with the classification of high-temperature ceramics, followed by the processing requirement of using sintering additives toward achieving full densification. Consequently, the technological aspect of optimizing the sintering conditions to attain uniform or controlled microstructure and, thereby, enhance performance of high-temperature ceramics is discussed in reference to recently developed TiB2 or ZrB2 ceramics with silicide additives. Following which, high-temperature oxidation and mechanical properties are detailed for better understanding of stable high-temperature ceramics for advanced applications.

Nanoceramic composites, a newly sustainable arena, are detailed in Section VI, demonstrating their relevance in today’s scenario. Processing-related challenges and microstructure development are described to illustrate how to develop strategies to retain their nanograined feature using some advanced sintering routes, for example, spark plasma sintering. The need for tailoring composition and process parameters is also presented in reference to recent development of oxide and non-oxide ceramic nanocomposites.

One of the important areas in which ceramics are receiving more appreciation is biomedical applications. After mentioning some of the concepts required for the development of bioceramics and biocomposites, the processing and properties of HAp-based bioceramic composites for hard-tissue replacement applications are addressed in Section VII. Furthermore, this final section concentrates on the in vitro and in vivo properties of bioceramic composites followed by assessment of their tribological properties, which is essential when evaluating new materials as potential biocomposite ceramics.

Hence, this book provides an entirely new paradigm of visualizing ceramics not only as an isolated category of materials limited to high-temperature wear and corrosion resistance, but also as load-bearing structural materials for advanced and new engineered and/or scientific applications. The previously described layout of the book as well as the succession of the various sections and chapters is primarily meant to provide easy understanding for both students and experts pursuing the field of structural ceramics. In particular, this book has the following major important features: (1) the fundamental structure–processing–property–application pyramid is presented, enabling the book to be used as a textbook for teaching, academics, and research; (2) a broad range of topics is covered, including contemporary and exciting areas such as advanced tough ceramics, high-temperature ceramics, advanced ceramic processing techniques, and the in vivo and in vitro properties of bioceramics; (3) the basics addressed in this book will appeal to a large number of active researchers from various disciplines—biological sciences, metallurgy and materials science, ceramics, and biotechnology—as well as engineers, manufacturers, dentists, and surgeons.

This book is the outcome of several years of teaching undergraduate- and postgraduate-level courses in the areas of ceramics, composite materials, biomaterials, manufacturing of materials, and other related fundamental courses in the area of materials science offered to students of the Indian Institute of Technology (IIT) Kanpur, India. More important, the research results of many of the postgraduate students from our research groups are also summarized in some chapters. Bikramjit Basu would like to mention the contribution of his past and present students, B. V. Manoj Kumar, G. Brahma Raju, Amartya Mukhopadhyay, Shekhar Nath, Naresh Saha, Shouriya Dutta Gupta, K. Madhav Reddy, Subhodip Bodhak, Srimanta Das Bakshi, D. Sarkar, P. Suresh Babu, Manisha Taneja, Amit S. Sharma, Garima Tripathi, Alok Kumar, Shilpee Jain, Neha Gupta, Ashutosh K. Dubey, Devesh Tiwari, Shibayan Roy, Ravi Kumar, A. Tewari, Prafulla Mallick, R. Tripathy, T. Venkateswaran, U. Raghunandan, Divya Jain, Nitish Kumar, Atiar R. Molla, and Sushma Kalmodia. The dedication of these students to developing various ceramics and composites is reflected in the research results summarized in many of the chapters. With a great sense of appreciation and gratitude, B. Basu notes past and present research collaboration with a number of researchers and academicians, including Drs. Omer Van Der Biest, Jozef Vleugels, G. Roebben, D. Dierickx, C. Zhao, R. K. Bordia, Dileep Singh, M. Singh, T. Goto, T. J. Webster, Amar S. Bhalla, Ruyan Guo, Mauli Agrawal, Artemis Stamboulis, G. Sundararajan, K. Chattopadhyay, K. Biswas, N. K. Mukhopadhyay, M. Banerjee, R. Gupta, D. Kundu, R. Prasad, S. K. Mishra, Mira Mohanty, P. V. Mohanan, A. K. Suri, Mike H. Lewis, Ender Suvaci, Hasan Mondal, Ferhat Kara, Nurcan Kalis Ackibas, D. Roy, M. C. Chu, S. J. Cho, Doh-Yeon Kim, J. H. Lee, Jo Wook, S. Kang, Alok Pandey, Alok Dhawan, Arvind Sinha, A. Basumallick, and Animesh Bose. The encouragement and collaboration with two of our former colleagues, the late Prof. R. Balasubramaniam and the late Prof. V. S. R. Murty, are also remembered. B. Basu also remembers the constant inspiration of a number of colleagues and former teachers, including Profs. S. Ranganathan, Ashutosh Sharma, Goutam Biswas, Kalyanmoy Deb, Vikram Jayaram, Dipankar Banerjee, Atul Chokshi, and B. S. Murty.

Kantesh Balani thanks the contribution of his students and staff: Dr. Neelima Mahato, Ankur Gupta, Milind R. Joshi, Samir Sharma, S. Ariharan, Anup Patel, and Raja Choudhary. He also expresses his sincere gratitude to long-term colleagues and friends: Dr. Debrupa Lahiri and Profs. Yao Chen, Srinivasa Rao Bakshi, Rajesh Srivastava, Sanjay Mittal, Ashwini Kumar, and Anup Keshri.

The authors also extend sincere gratitude to their colleagues at the Materials Science and Engineering Department at IIT Kanpur, especially Profs. Dipak Mazumdar, S.P. Mehrotra, Anandh Subramaniam, Anish Upadhyaya, Gouthama, Kallol Mondal, Krishanu Biswas, Rajiv Shekhar, Monica Katiyar, Deepak Gupta, and Vivek Verma, for their consistent support. The authors express their sincere thanks to Mr. Divakar Tiwari for his untiring efforts and excellent assistance during the manuscript preparation.

The authors would like to take this opportunity to acknowledge the finan­cial support of various governmental agencies of India, including the Council of Scientific and Industrial Research (CSIR), Department of Atomic Energy (DAE), Department of Biotechnology (DBT), Ministry of Human Resource and Development (MHRD), Defense Research and Development Organization (DRDO), Department of Science and Technology (DST), UK–India Education and Research Initiative (UKIERI), and Indo–US Science and Technology Forum (IUSSTF), which facilitated research in the area of ceramics and composites in our group. We would also like to thank the CARE grant, and the Centre for Development of Technical Education (CDTE), IIT Kanpur, for extending financial support during the writing of this book. Bikramjit Basu expresses gratitude to his long-time friend and collaborator, Dr. Jaydeep Sarkar, for constant inspiration during the writing of this book. Kantesh Balani also extends his sincere gratitude for the tutelage and support extended by Prof. Arvind Agarwal, Florida International University, Miami. We thank Prof. Sir Richard Brook for constructive criticism and comments.

The authors sincerely express their gratitude to Prof. Michel Barsoum for writing the Foreword.

Finally, we acknowledge the moral support extended by our parents, in-laws, and family members during the course of writing this book.

BIKRAMJIT BASU

Laboratory of Biomaterials

Materials Science and Engineering

IIT Kanpur, India

Currently at the Materials Research Center

Indian Institute of Science

Bangalore, India

KANTESH BALANI

Biomaterials Processing and Characterization Laboratory

Materials Science and Engineering

IIT Kanpur, India

July 2011

To view color versions of the figures in this book, please visit ftp://ftp.wiley.com/public/sci_tech_med/advanced_structural_ceramics.

Foreword

Ceramics have long been recognized as brittle materials, which in turn has limited their applications. With the advent of tougher ceramics, however, their utility has increased concomitantly. This book explains how, and why, today advanced structural ceramics represent a multibillion dollar industry that is still growing. Ceramics are increasingly used in both monolithic and composite form in advanced aerospace, automotive, biomedical, industrial, and consumer applications. The vast majority of books dealing with the topic of structural ceramics and their uses are edited compilations or conference proceedings that are of little use for somebody trying to get a better handle on the topic. Since they are geared toward researchers and scientists who are more or less familiar with the topics at hand, these compilations do not attempt to explain the fundamental science behind the topics they discuss. This book tries to bridge the gap from basics to applications.

This book is divided into seven sections. The first introduces ceramics and the basics behind their bonding, as well as their mechanical properties and how they are quantified. The second section deals with the synthesis of ceramics powders and their compaction and sintering. The third reviews coatings and the thermal spray of ceramics. Section IV deals with the toughening of zirconia, SiAlONs, and the MAX phases. Section V considers ultra-high-temperature ceramics and their processing, mechanical properties, and oxidation resistances. The penultimate section reviews work on nanostructured ceramics, in both monolithic and composite form. The last section deals with bioceramics and their uses.

One of the major strengths of this book is the large number of examples and references—many from the authors’ own work—used to illustrate the ideas presented. Another advantage of this book is that it is conceived, from the initial stages, as a textbook and is based in part on the authors’ class notes, which from my experience is a valuable and almost indispensible requirement for writing a good textbook. This book can be used as a textbook for students—both graduate and senior undergraduate—and academicians, or as a practical guide for industrial researchers and engineers.

MICHEL W. BARSOUM

Grosvenor and Distinguished Professor

Department of Materials Science and Engineering

Drexel University, Philadelphia, PA

About the Authors

Dr. Bikramjit Basu is currently an Associate Professor, Materials Research Center, Indian Institute of Science, Bangalore, India. He is on leave from the Indian Institute of Technology (IIT) Kanpur, India. Bikramjit Basu obtained his undergraduate and postgraduate degrees, both in metallurgical engineering, from National Institute of Technology, Durgapur, and the Indian Institute of Science, Bangalore, in 1995 and 1997, respectively. He earned his PhD in ceramics at Katholieke Universiteit Leuven, Belgium, in 2001. After a brief stint of postdoctoral research at University of California, Santa Barbara, he joined IIT Kanpur, India, in 2001 as assistant professor. He has held visiting positions at University of Warwick, U.K., Seoul National University, South Korea, and University Polytechnic Catalonia, Barcelona. In India, Dr. Basu established vibrant research programs in ceramics and biomaterials with government funding of more than five crores. In the structural ceramics area, he demonstrated the unique capability of spark plasma sintering in developing nanoceramic materials in zirconia (ZrO2) and tungsten carbide (WC) systems. In biomaterials, his primary focus is on optimizing the physical and biological properties in hydroxyapatite-based biocomposites and glass-ceramics for hard-tissue replacement.

Dr. Basu has authored or co-authored more than 150 peer-reviewed research papers, including 20 papers in Journal of American Ceramic Society. He has delivered more than 80 invited lectures, both nationally and internationally, including in the United States, United Kingdom, Germany, Japan, and Canada. He is on the editorial board of five international journals (including Materials Science and Engineering C and International Journal of Biomaterials) and serves as reviewer of more than 20 Science Citation Index journals in the area of ceramics and biomaterials. He is principal editor of the book Advanced Biomaterials: Fundamentals, Processing and Applications (which was published in September 2009 by John Wiley & Sons). He is currently the principal investigator of two major international research programs in biomaterials, funded by UK–India Educational and Research Initiative and Indo–US Science and Technology Forum. In recognition of his contributions to the fields of ceramics, tribology, and biomaterials, Dr. Basu received noteworthy awards from the Indian Ceramic Society (2003), Indian National Academy of Engineering (2004), and Indian National Science Academy (2005), as well as the Metallurgist of the Year award (2010), instituted by Ministry of Steels, Government of India. He is the first Indian from India to receive the prestigious Coble Award for Young Scholars from the American Ceramic Society in 2008. Recently, he received the National Academy of Science, India (NASI)-SCOPUS Young Scientist 2010 award in Engineering Sciences.

Dr. Kantesh Balani joined as an assistant professor in the Department of Materials and Metallurgical Engineering (now Materials Science & Engineering) at the IIT Kanpur in July 2008. He earned his doctorate in mechanical engineering from Florida International University, Miami, in 2007. His research concentrated on the role of carbon nanotube dispersion in enhancing the fracture toughness of alumina (Al2O3) nanocomposites. He has also worked on bioceramic hydroxyapatite coatings for biomedical applications. He pursued his postdoctoral research in the Nanomechanics and Nanotribology Laboratory (NMNTL) and Plasma Forming Laboratory (PFL), Florida International University, Miami. He is recipient of several fellowships and awards, such as Young Engineer Award 2010 (Indian National Academy of Engineering), Young Metallurgist Award 2010 (Indian Institute of Metals), Young Scientist Award 2009 (Materials Science Division, Indian Science Congress Association), R.L. Thakur Memorial Prize 2009 (Indian Ceramics Association), David Merchant International Student Achievement Award 2007, Arthur E. Focke LeaderShape Award 2004, Research Challenge Trust Fund (RCTF) Fellowship 2002, Sudharshan Bhat Memorial Prize and S. Ananthramakrishnan Memorial Prize 2001, and Deutscher Akademischer Austausch Dienst (DAAD) Scholarship 2001. He has presented over 25 lectures at international conferences and has over 45 publications in peer-reviewed journals and conference proceedings. His research interests include ab initio molecular modeling, electron microscopy, and nanomechanics and nanotribology of bio/nanocomposites. Currently, he is reviewer of over 20 technical journals from Elsevier, Blackwell Publishing Inc., Wiley, Springer, Hindawi, Highwire, Materials Research Society India/Indian National Science Academy, and American Society of Metals, serves as a key reader for Metallurgical and Materials Transactions A, and is involved as one of the editorial board members of Recent Patents on Materials Science (Bentham), Recent Patents on Nanotechnology (Bentham), and Nanomaterials and Energy (Institution of Civil Engineers).

Section One: Fundamentals of Nature and Characteristics of Ceramics

Chapter 1

Ceramics: Definition and Characteristics

In this chapter, the general properties of ceramics are discussed in reference to other primary classes of materials. Further, the need for the development of high-toughness ceramics with high hardness, strength, and wear resistance are addressed. The development of ceramic materials for high-temperature applications are also discussed.

1.1 MATERIALS CLASSIFICATION

There is a general consensus that engineering materials can be classified into three primary classes: metals and alloys; ceramics and glasses; and polymers. Among these three primary classes, metals, metallic alloys, and polymers are, by far, more widely used than ceramics and glasses for various structural and engineering applications. Nevertheless, ceramics have attracted attention in the scientific community in the last three decades.1–4 The widespread use of metallic materials is driven by their high tensile strength and high toughness (crack growth resistance) as well as their ability to be manufactured in various sizes and shapes using reproducible fabrication techniques. Similarly, polymers have distinct advantages in terms of their low density, high flexibility, and ability to be molded into different shapes and sizes. Nevertheless, polymeric materials have low melting point (less than 400°C) as well as very low strength and elastic modulus. Compared with ceramics, metals have much lower hardness and many commonly used metallic materials have a much lower melting point (<2000°C). From this perspective, ceramics and glasses have advantageous properties, including refractoriness (capability to withstand high temperatures), strength retention at high temperature, high melting point, and good mechanical properties (hardness, elastic modulus, and compressive strength). In view of such an attractive combination of properties, ceramics are considered as potential materials for high-temperature structural applications and various tribological applications requiring high hardness and wear resistance. Despite having such potential applications, the widespread use of ceramics has been limited, because of their brittleness (poor fracture toughness) and variability in mechanical properties.

To combine various advantageous properties of the three primary material classes, a derived material class—that is, composites—is being developed. The composites are generally defined as a class of materials that comprise at least two intimately bonded microstructural phases aimed to provide properties (e.g., elastic modulus, hardness, strength) tailored for specific applications; it is expected that a specific property of a composite should be higher than the simple addition of that property of the constituent phases. Depending on whether metals, ceramics, or polymers comprise more than 50% by volume of a composite, it can be further classified as a metal matrix composite (MMC), a ceramic matrix composite (CMC), or a polymer matrix composite (PMC) respectively. From the microstructural point of view, a composite contains a matrix (metal, ceramic, polymer) and a reinforcement phase. The crystalline matrix phase can have an equiaxed or elongated grain structure; the reinforcement phase can have different shapes, for example particulates, whiskers, and fibers. The reinforcement shapes can be distinguished in terms of aspect ratio: particulates can be spheroidal; whiskers have a higher aspect ratio (>10); fibers have the largest aspect ratio. It is widely recognized now that the use of fibers or whiskers can lead to composites with anisotropic properties (different properties in different directions). As far as nomenclature is concerned, it is a common practice to designate a composite as M-Rp, M-Rw, or M-Rf, where M and R are the matrix and reinforcement, respectively, and the subscripts (p, w, f) essentially indicate the presence of reinforcement as particulates, whiskers, or fibers, respectively. One widely researched MMC is Al–SiCp composite; Mg–SiCp is being developed as a lightweight composite; several MMCs are used as automotive parts and structural components. Some popular examples of CMCs include Al2O3–ZrO2 p and Al2O3–SiCw; these CMCs are typically used as wear parts and cutting-tool inserts. Various resin-bonded PMCs are used for aerospace applications.

1.2 HISTORICAL PERSPECTIVE; DEFINITION AND CLASSIFICATION OF CERAMICS

As far as the history of ceramics is concerned, the word “ceramics” is derived from the Greek word keramikos, literally meaning potter’s earth. Historically, the use of burnt clay, commercial pottery, and the existing ceramic industries can be dated back to 14,000 BC, 4000 BC, and 1500 BC, respectively. Early evidence of the use of clay- or pottery-based materials has been found in Harappan, Chinese, Greek, and many other civilizations. A large number of traditional ceramics were produced using conventional ceramic technology. Early forms of color decorative glazes date back to 3500 BC. The potter’s wheel, invented around 2000 BC, revolutionized pottery making; porcelain emerged in China circa 600 AD. Glazed tiles were used to decorate the walls of the famous Tower of Babel and the Ishtar Gate in the ancient city of Babylon (562 BC). Figure 1.1 indicates the growth in ceramic technology from prehistoric ages to the 20th century. It is clear that, with technological development, some newer applications in high-tech and important areas, for example the biomedical and electronics industries, are now possible.

Figure 1.1 Historical evolution illustrating the growth of ceramic applications and industries.30

A proper and exact definition of ceramics is very difficult. In general, ceramics can be defined as a class of inorganic nonmetallic materials5 that have ionic and/or covalent bonding and that are either processed or used at high temperatures. Figures 1.1–1.4 illustrate two different aspects: (1) historical evolution of the development of ceramics right from traditional ceramics to the most advanced ceramics to composites and (2) illustration of various current uses of ceramics and their composites. For a layperson, the word “ceramic” means a coffee cup or sanitary ware—traditional ceramic products. Although the main use of ceramics in last few decades was centered on fields such as construction materials, tableware, and sanitary wares, the advancement of ceramic science since the early 1990s has enabled the application of this class of materials to evolve from more traditional fields to cutting-edge technologies, such as aerospace, nuclear, electronics, and biomedical, among others.6 This is the reason that, in many textbooks, ceramics are classified as traditional ceramics and engineering ceramics. Traditional ceramics are largely silica or clay based and typically involve low-cost fabrication processes. A large cross section of people in the developing world is still familiar with the use of traditional ceramics. On the other hand, engineering ceramics are fabricated from high-purity ceramic powders, and their properties can be manipulated by varying process parameters and, thereby, microstructures. Also, engineering ceramics are, by far, more expensive than traditional ceramics. In this textbook, our focus is on discussing the structure, processing, properties, and applications of engineering ceramic systems, particularly on structure–property correlations. Based on their applications, engineering ceramics are usually classified into two major classes: structural ceramics and functional ceramics. While the applications of structural ceramics demands the optimization of mechanical strength, hardness, toughness, and wear resistance,7 the performance of functional ceramics is controlled by electric, magnetic, dielectric, optical, and other properties.6 In general, structural ceramics can be further classified into two classes: (1) oxide ceramics (Al2O3, ZrO2, SiO2, etc.) and (2) non-oxide ceramics (SiC, TiC, B4C, TiB2, Si3N4, TiN, etc.). Various chapters in this textbook focus only on several structural ceramics. Nevertheless, the crystal structure of some important functional ceramics is discussed in Chapter 2.

Figure 1.2 The illustrative examples of the use of engineering ceramics: silicon nitride (Si3N4) ceramic cutting tool inserts and components (a), silicon nitride check valve balls ranging from around 20 mm to around 40 mm in diameter (b) and silicon nitride–based experimental automobile valve (c).30

Figure 1.3 The use of silicon carbide seals as structural components.30

Figure 1.4 Another emerging area of oxide ceramics is shown: tubular solid oxide fuel cell module (a) and experimental planar SOFC module (b).30

1.3 PROPERTIES OF STRUCTURAL CERAMICS

In general, ceramics have many useful properties, such as high hardness, stiffness, and elastic modulus, wear resistance, high strength retention at elevated temperatures, and corrosion resistance associated with chemical inertness.7 The temporal progression of the development of advanced ceramics is presented in Figure 1.1. It has been reported that a flexural strength of more than 1 GPa can now be achieved in oxide ceramics and that a specific strength (strength-to-density ratio) of more than 2 can be obtained in some composites. Overall, a 50-fold increase in specific strength is now achievable in advanced ceramics, compared with that in primitive traditional ceramics. While various industries have still been mostly using high-speed tool steels, a 10-fold increase in cutting speed can be obtained with the use of ceramic- or cermet-based tool inserts. As far as the maximum operating temperature is concerned, Ni-based superalloys are typically used at 1000°C. In contrast, some nitride and some oxide ceramics can be used at temperatures of close to 1500°C. Although polymers have the lowest density, many of the ceramics (alumina, SiC) have half the density of steel-based materials. Therefore, high-speed turning or cutting operations are possible with ceramic- or cermet-based tool inserts. More often, density becomes a limitation or a requirement in selecting the ceramics for structural, defense, biomedical, and other applications: bone implants require density similar to that of bone; aerospace applications require minimal density with exceptional creep-resistance; and high-energy penetrators aim for high-density counterparts. In terms of elastic modulus or hardness, ceramics are much better than all the refractory metals. As an example of the hardness of commonly known ceramics, that of Al2O3 is around 19 GPa, which is close to 3 times the hardness value of fully hardened martensitic steel (∼7 GPa). As is discussed in this book, many ceramics, such as TiB2, can have hardness of around 28 GPa or higher. Also, the elastic modulus of Al2O3 is around 390 GPa, which is close to double that of steels (210 GPa). The higher elastic modulus of ceramics provides them with good resistance to contact damage. In addition, many ceramics, such as SiC and Si3N4, can exhibit high-temperature strength in the temperature range, where metallic alloys soften and cannot be used for structural applications. Many of these properties are realized in many of the hi-tech applications of ceramics, which include rocket nozzles, engine parts, bioceramics for medical implants, heat-resistant tiles for the space shuttle, nuclear materials, storage and renewable energy devices, and elements for integrated electronics such as microelectromechanical systems (MEMS).

Despite having many attractive properties, as just mentioned, the major limitations of ceramics for structural and some nonstructural applications is their poor fracture toughness. Over the years, it has been realized that an optimum combination of high toughness with high hardness and strength is required for the majority of the current and future applications of structural ceramics, including biomaterials (see Section Seven). To address this need, the development of ceramic composites with optimal combinations of mechanical properties is the major focus in the ceramics community.

1.4 APPLICATIONS OF STRUCTURAL CERAMICS

As mentioned earlier, ceramics are examples of high-temperature materials, which are used specifically for their high-temperature strength, hot erosion, and resistance to corrosion or oxidation at temperatures above 500°C. The need for high-temperature materials has been realized in different sectors of industry, including high-temperature machining, material production and processing, chemical engineering, high-temperature nuclear reactors, aerospace industries, power generation, and transportation, among others.

Typical examples of areas wherein engineering ceramics have found applications are illustrated in Figures 1.2–1.4. Figure 1.2 shows Si3N4-based materials as ball bearings, automobile valves, and cutting inserts; Figure 1.3 shows SiC used as bearing seals. In Figure 1.4, a solid oxide fuel cell (SOFC) module is shown; oxide ceramics, such as zirconia, are widely used in SOFCs. There exists a clear demand for materials that can withstand more than 1500°C; such applications include re-entry nozzles in rockets or hypersonic space vehicles. To this end, ultra-high-temperature ceramics (UHTCs) based on borides are being developed (see Section Five). Because of their high melting point, high hardness, electrical and thermal conductivity, and high wear resistance, the borides of transition metals, such as TiB2, are used for a variety of technological applications.8 Monolithic TiB2, that is, without any second phase addition, has excellent hardness (≈25 GPa at room temperature), good thermal conductivity (≈64 W/m·°C), high electrical conductivity (electrical resistivity ≈13 × 10−8 m) and considerable chemical stability.9 Some of these attractive properties are ideally suited to be exploited for tribological applications. However, the relatively low fracture toughness (≈5 MPa m1/2) and modest bending strength (≈500 MPa) coupled with poor sinterability of monolithic TiB2 limits its use in many engineering applications.10 In the materials world, TiB2 is often used as reinforcement phase not only for ceramics, but also for metallic alloys such as stainless steel11 and Al-alloys12 to develop composites with improved abrasive wear resistance. The addition of TiB2 to an Al2O3 or B4C matrix increases its hardness, strength, and fracture toughness.13 Furthermore, TiB2 as well as TiN or TiC, is used not only to toughen Al2O3 and Si3N4 matrices, but also to obtain electroconductive materials with the incorporation of an optimum amount of an electroconductive phase.14 These electroconductive toughened ceramics can be shaped by electrodischarge machining (EDM) to manufacture complex components, greatly increasing the number of industrial applications of these ceramic materials. The processing–property relationships of borides are discussed in one of the sections in this book, and the way sinter-aids and sintering conditions can be optimized to develop borides with high sinter density and a better combination of physical and mechanical properties is illustrated.

One application that has attracted much attention is ball bearings (see Fig. 1.2). Ceramic balls enclosed in a steel race, that is, hybrid bearings, are now used in turbopumps of the space shuttle main engine. The friction and wear properties of alumina, zirconia, and SiC in cryogenic environments are being investigated as such studies are relevant to cryotribological applications.15–17 These ceramic balls are commercially available with diameters from 4 mm to as large as 20–30 mm and they are made from Al2O3, ZrO2, SiC, Si3N4, or SiAlON (Si6−zAlzOzN8−z, with z being the substitution level). Commercial springs made of silicon nitride materials are also available. In one of the sections of this book, the microstructure and mechanical properties of such ceramics are discussed.

There is a tremendous industrial need for new tribological materials. This need is realized in metal-forming industries, bearings, gears, valve guides and tappets in engines, seals and bearings involving fluid and gas transport, often under corrosive conditions, and so on. The majority of these applications are currently served by hardened steels and WC-based hardmetals with or without surface coatings. However, new materials or improved existing materials are needed to meet the increasing demand in the tribological world. Ceramics, because of their ionic and/or covalent bonding, have a useful combination of physicomechanical properties (elastic modulus, hardness, and strength) and corrosion resistance. In many structural and tribological applications, ceramics are recognized as having great potential to replace existing materials for a series of rubbing-pairs, such as seal rings, valve seats, extrusion dies, cutting tools, bearings, and cylinder liners.18 The materials of interest will have to combine high hardness, toughness, strength, elastic modulus, and wear resistance coupled with relatively low density, resulting in low inertia under reciprocating stresses. Furthermore, the fundamental understanding of the relationship between composition, microstructure, processing route, mechanical properties, wear behavior, and performance should be clarified in order to optimally use the engineered materials in tribological applications. The development of new tribological materials is proceeding in two main directions: the use of coatings on conventional metallic substrates and the use of monolithic ceramics and ceramic composites.

Coatings are frequently hard carbides, nitrides, or borides with recent development of diamond or diamondlike (C–H) films at the more exotic end of the hardness-versus-cost scale.19 Coating thickness is normally between 1 and 50 µm, depending on the deposition process (physical vapor deposition [PVD], chemical vapor deposition [CVD], or electrolytic), which presents limitations in lifetime or property influence of the relatively soft substrate. Thicker coatings may be applied by thermal spraying (in the millimeter range) but are limited in chemistry, compatibility with substrate properties (thermal expansion etc.), and cohesion. An entire section of this textbook focuses on the discussion of processing and properties of coatings (Section Three).

Monolithic ceramics, especially those with improved strength and toughness, have been a focus of development in different research labs and industries since the 1970s.20 However, monolithic ceramics are not optimal for all engineering applications. Ceramic composites such as metal matrix and PMCs are now the established approaches to designing structural materials.21 Ceramic reinforcements are commercially available in different forms such as whiskers, platelets, particulates, and fibers. Two major classes of ceramic composites are fiber-reinforced and particle- or whisker-reinforced ceramic composites. A popular example of the first class of ceramic composites is silicon carbide fiber-reinforced glass-ceramics.22 The alumina–silicon carbide whisker-reinforced composites are commercially fabricated for use as drilling components. Four major drawbacks normally restrict the widespread use of this material class for structural applications: high cost of ceramic fibers; the expensive composite production route; the chemical compatibility of the fiber with the matrix; and the oxidation of SiC fibers at high temperatures. To this end, particle-reinforced CMCs offer a viable and relatively cost-effective option for developing materials with improved and optimal combinations of mechanical properties (hardness, toughness, and strength).

In the world of ceramic materials, yttria-doped zirconia, in particular yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics, are regarded as a strong candidate for structural applications due to the excellent addition of strength (≈700–1200 MPa) and fracture toughness (2–10 MPa m1/2) in addition to good chemical inertness.23,24 The high toughness of the zirconia monoliths stems from the stress-induced transformation of the tetragonal (t) phase to the monoclinic (m) phase in the stress field of propagating cracks, a concept widely known as transformation toughening.25 Basic microstructural requirements for the effective contribution from transformation toughening is the maximum retention of the tetragonal phase at the application temperature with sufficient transformability to m-ZrO2 in the crack tip stress field. The concepts and microstructural parameters influencing transformation toughening are discussed in Section Four. Since the discovery of the concept of transformation toughening about two decades ago,26 this approach has been successfully utilized to toughen several intermetallic,27 glass,28 and ceramic29 microstructures. More recently, extensive efforts have been put into increasing the toughness of alumina by adding zirconia, a class of materials known as zirconia-toughened alumina (ZTA).17,19

The successful application of engineering ceramic components demands the careful selection and optimization of the initial material (i.e., powder purity, size, shape, etc.) followed by its optimal sintering (time, temperature, pressure, and environment to control grain size and densification) for achieving appropriate properties. These aspects necessitate that researchers consider the selection–processing–property–application tetrahedron, as shown in Figure 1.5.

Figure 1.5 Selection–processing–property–application tetrahedron of ceramics.

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