HANDBOOK OF REFRACTORY
`CARBIDES AND NITRIDES
`
`Properties, Characteristics,
`Processing and Applications
`
`by
`
`Hugh 0. Pierson
`
`Consultant and Sandia National Laboratories (retired)
`Albuquerque, New Mexico
`
`r::l NOYES PUBLICATIONS
`
`~ Westwood, New Jersey, U.S.A.
`
`IPR2015-01087 - Ex. 1019
`Micron Technology, Inc., et al., Petitioners
`1
`
`

`

`Copyright Q 1996 by Noyes Publications
`No part of this book may be ~produced or utilized
`in any form or by any means, electronic or
`mechanical, including photocopying, ~cording or
`by any infonnation storage and retrieval system,
`without permission in writing from the Publisher.
`Library of Congress Catalog Card Number: 96-12.578
`ISBN: 0-8JS.5-1392-S
`Printed in the United States
`
`Published in the United States of America by
`Noyes Publications
`369 Fairview Avenue, Westwood, New Jersey 0767.5
`
`10 9 8 7 6 5 4 3 2 I
`
`Library of Congress Cataloging-in-Pub! ication Data
`
`Pierson, Hugh 0.
`Handbook of refractory carbides and nitrides : properties,
`characteristics, processing, and applications I by Hugh 0 . Pierson.
`em.
`p.
`Includes bibliographical references and i.ndex.
`ISBN 0-81.55-1392-.5
`I. Refractory transition metal compounds--Metallography.
`I. Title
`2. Carbides. 3. Nitrides
`TN693.T7P.54 1996
`666'.72-dc20
`
`96-12S78
`CIP
`
`MJl
`
`Rointaa
`Gary E
`St ephe
`(ConSL
`
`HAN DB
`Edition:
`
`C HEMit
`
`SEMIC t
`by Gary
`
`HYBRIC
`Enlow
`HAN DB
`Klaus K
`
`IONIZE
`
`DIFFU~
`edtled t
`HAN DB
`Donald
`HAN DB
`Stepher
`
`CHARA
`McGuirt
`HAN DB
`Jerome
`
`HAN DB
`O'Mara,
`HAN DB
`Licari at
`
`HAN DB
`Hayaka·
`HAN DB
`N. Helb•
`
`CHEMI~
`
`CHEMI<
`E. J . Sc
`
`ELECTI
`Me Hard
`
`HAN DB
`
`

`

`ds, Arthur Mullendore,
`~k Stiglich, fonnerly of
`thorough review of the
`1 friend, George Narita,
`elp and patience in the
`
`Hugh 0 . Pierson
`
`Contents
`
`this publication is
`lY responsibility or
`or consequences
`d for infonnational
`nrnercial products
`tion for use by the
`of any information
`the manner of that
`! recommend that
`on of materials or
`I satisfy himself as
`1licable safety and
`
`1 Introduction ............................................................. 1
`1.0 HISTORICAL PERSPECTIVE AND PRESENT STATUS OF
`REFRACTORY CARBIDES AND NITRIDES ....................... l
`2.0 CARBIDES AND NITRIDES AS REFRACTORY
`MATERIALS
`....................................................................... 2
`3.0 BOOK OBJECTIVES ............................................................. 3
`4.0 BOOK ORGANIZATION ....................................................... 4
`5.0 GLOSSARY AND METRIC CONVERSION GUIDE ............ 5
`6.0 BACKGROUND READING ................................................... 5
`6.1 General References ............................................................ 5
`6.2 Periodicals ....................................................................... 6
`6.3 Conferences ........................................................ ~ .............. 7
`
`2 The Refractory Carbides ........................................ 8
`1.0 INTRODUCTlON .................................................................. . 8
`2.0 DEFINITION AND CLASSIFICATION OF CARBIDES ....... 8
`2.1 Classification ..................................................................... 9
`2.2 Refractory Qualifications ................................................... 9
`2.3 Factors Controlling Carbide Formation .............................. 9
`3.0 CARBIDE FORMATION AND ELECTRONEGATMTY ..... 9
`3.1 Definition of Electronegativity ........................................... 9
`3.2 Comparison of Electronegativity ...................................... 10
`
`ix
`
`

`

`x
`
`Contents
`
`4.0 CARBIDE FORMATION AND ATOM SIZE ....................... 11
`4.1 Atomic Radius ................................................................. 11
`4.2 Carbide Formation and Ratio of Atomic Radii .................. 12
`5.0 THE ATOMIC BONDING OF CARBIDES .......................... 12
`5.1 Ionic Bond ......... : ........................................................... 12
`5.2 Covalent Bond ............ ..................................................... 13
`5.3 Metallic Bond ............. ..................................................... 14
`6.0 GENERAL CHARACTERISTICS OF CARBIDES .............. 14
`6.1' Interstitial Carbides ......................................................... 14
`6.2 Covalent Carbides ........................................................... 14
`6.3 Intermediate Carbides . .. .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . 15
`6.4 Salt-Like Carbides ........................................................... 15
`REFERENCES
`..................................................................... 16
`
`3 Interstitial Carbides, Structure and Composition ... 17
`1.0 DEFTNITION AND GENERAL CHARACTERISTICS OF
`INTERSTITIAL CARBIDES ................................................ 17
`1.1 Definition
`..................................................................... 17
`1.2 General Characteristics .................................................... 18
`2.0 ELECTRONIC STRUCTURE OF CARBON ........................ 18
`2.1 Nucleus and Electronic Configuration of the Carbon Atom ... 19
`2.2 Hybridization of the Carbon Atom ......... · .......................... 22
`2.3 The sp3 Bond ................................................................... 24
`3.0 THE EARLY TRANSITION METALS ................................ 25
`3.1 Definition ofTransition Elements ..................................... 25
`3.2 Electronic Configuration of Early Transition Metals ......... 26
`4.0 CRYSTAL STRUCTURES ................................................... 27
`4.1 Close-Packed Crystalline Structures ................................. 27
`4.2 Hexagonal Close-Packed (hcp) and Face-Centered
`Cubic Close-Packed (fcc) Structures ................................ 28
`4.3 Body-Centered Cubic (bee) and Simple Hexagonal
`Structures
`..................................................................... 31
`4.4 Crystal Structures of Early Transition Metals .................. 31
`5.0 ATOMIC STRUCTURE OF INTERSTITIAL CARBIDES ... 34
`5.1 Definition oflnterstitial Structures ................................... 34
`5.2 Atomic-Radii Ratio ....... ................................................... 34
`5.3 Interstitial Sites ................................................................ 34
`5.4 The Chromium Carbide Exception ................................... 36
`6.0 CRYSTALLINE STRUCTURE AND COMPOSITION OF
`INTERSTITIAL CARBIDES ................................................ 36
`6. 1 Crystalline Structure ........................................................ 36
`6.2 Composition and Structure ............................................... 37
`
`6.3 Metal-to-<
`6.4 Density 0
`7.0 ATOMIC BOl
`7 . I Complexi~
`7.2 Overall Be
`7.3 Thermal P1
`7.4 Ionic Bond
`7.5 Covalent E
`7.6 Bonding ar1
`7. 7 Metallic B<
`7. 8 Band Struc
`8. 0 INTERSTITIA
`8.1 Vacancies
`8.2 Ordering of
`9.0 GENERAL RE
`lNTERSTITIAJ
`9.1 Variations u
`9.2 General Ch'
`REFERENCES
`
`4 Carbides of Gr
`Hafnium Carbi
`1. 0 GENERAL CHi
`GROUP IV CAF
`2.0 PHYSICAL AN1
`GROUP IV CAR
`2.1 Density and I
`2.2 Thermal Pro1
`2.3 Thermodynar
`2.4 Thermal Con1
`2.5 Thermal Exp;
`3.0 ELECTRICAL p;
`3.1 Electrical Cor
`3.2 Hall Effect ..
`4.0 MECHANICAL J
`4.1 Property Vari;
`4.2 Summary of 1
`4.3 Failure Mecha
`4.4 Ductile-Brittle
`...
`4.5 Hardness
`4.6 Transverse Ru.
`
`

`

`~TOM SIZE ....................... 11
`........................................... 11
`of Atomic Radii .................. 12
`ARBIDES .......................... 12
`··········································· 12
`........................................... 13
`........................................... 14
`:s OF CARBIDES .............. 14
`············································ 14
`............................................ 14
`............................................ 15
`............................................ 15
`............................................ 16
`
`re and Composition ... 17
`CHARACTERISTICS OF
`............................................ 17
`............................................ 17
`············································ 18
`1F CARBON ........................ 18
`;uration of the Carbon Atom ... 19
`Atom ......... · .......................... 22
`............................................ 24
`~TALS ................................ 25
`1ents ..................................... 25
`iarly Transition Metals ......... 26
`............................................ 27
`uctures ................................. 27
`p) and Face-Centered
`uctures ................................ 28
`llld Simple Hexagonal
`............................................. 31
`'ransition Metals .................. 31
`TERSTITIAL CARBIDES ... 34
`ctures ................................... 34
`............................................. 34
`............................................. 34
`:ption ................................... 36
`AND COMPOSITION OF
`............................................. 36
`............................................. 36
`............................................. 37
`
`Contents xi
`
`6.3 Metal-to-Carbide Structural Switching ............................. 39
`6.4 Density Considerations .................................................... 40
`7.0 ATOMIC BONDING OF INTERSTITIAL CARBIDES ....... 41
`7.1 Complexity of Bondjng System ........................................ 41
`7.2 Overall Bonding Scheme .................................................. 42
`7.3 Thennal Properties Considerations ................................... 42
`7.4 Ionic Bonding and Elcctronegativity ................................. 46
`7.5 Covalent Bonding in lnterstitjaJ Monocarbides ................. 46
`7.6 Bonding and Atomic Spacing ........................................... 47
`7. 7 Metallic Bonding ............................................................. 48
`7.8 Band Structure ................................................................ 48
`8.0 INTERSTITIAL CARBIDES AS DEFECT STRUCTURES . 48
`..................................................................... 48
`8.1 Vacancies
`8.2 Ordering of the Carbon Atoms ......................................... 50
`9.0 GENERAL REVIEW OF THE PROPERTIES OF
`INTERSTITIAL CARBIDES ................. , .............................. 51
`9. 1 Variations in Properties and Composition ......................... 51
`9.2 General Characteristics .................................................... 51
`..................... ~ ............................................... 52
`REFERENCES
`
`4 Carbides of Group IV: Titanium, Zirconium, and
`Hafnium Carbides ................................................ 55
`1.0 GENERAL CHARACTERISTICS OF
`GROUP IV CARBIDES ........................................................ 55
`2.0 PHYSICAL AND 1HERMAL PROPERTIES OF
`GROUP IV CARBIDES ........................................................ 56
`2.1 Density and Melting Point.. .............................................. 56
`2.2 Thennal Properties .......................................................... 57
`2.3 Thennodynamic Functions ......................................... ...... 58
`2.4 Thennal Conductivity ...................................................... 58
`2.5 Thennal Expansion .......................................................... 61
`3.0 ELECTRICAL PROPERTIES OF GROUP IV CARBIDES .. 62
`3.1 Electrical Conductivity .................................................... 62
`3 . 2 Hall Effect .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. .. .. .. .. .. .. .. . 64
`4.0 MECHANICAL PROPERTIES OF GROUP IV CARBIDES 64
`4.1 Property Variables ........................................................... 64
`4.2 Summary of Mechanical Properties ................................. 65
`4.3 Fa.ilure Mechanism ... , ...................................................... 65
`4.4 Ductile-Brittle Transition ................................................. 66
`4.5 Hardness
`..................................................................... 66
`4.6 Transverse Rupture Strength ............................................ 66
`
`

`

`--------------~;~ ............
`
`xii Contents
`
`~-
`
`5.0 CHEMICAL PROPERTIES OF GROUP IV CARBIDES ..... 68
`5.1 Mutual Solubilities ....................................................... ... 68
`5.2 Chemical Properties ......................................................... 68
`6.0 CHARACTERISTICS AND PROPERTIES OF
`TITANIUM CARBlDE ......................................................... 68
`6.1 Summary of Properties .................................................... 68
`6.2 Phase Diagram ................................................................ 72
`6.3 Summary of Fabrication Processes .................................. 72
`6.4 Summary of Applications and Industrial Importance ........ 72
`7.0 CHARACTERISTICS AND PROPERTIES OF
`ZIRCONIUM CARBIDE ...................................................... 73
`7.1 Summary of Properties .................................................... 73
`7.2 Phase Diagram .................. .............................................. 74
`7.3 Summary of Fabrication Processes ................. .............. ... 74
`7.4 Summary of Applications and Industrial Importance ........ 74
`8.0 CHARACTERJSTICS AND PROPERtiES OF
`HAFNlUM CARBIDE .......................................................... 76
`8. 1 Summary of Properties .................................................... 76
`8.2 Phase Diagram ................................................................ 77
`8.3 Summary of Fabrication Processes ................................... 78
`8.4 Summary of Applications and Industrial Importance ....... 78
`REFERENCES
`..................................................................... 78
`
`5 Carbides of Group V: Vanadium, Niobium and
`Tantalum Carbides #···································'I··········· 81
`1.0 GENERAL CHARACTERISTICS OF
`GROUP V CARBIDES ......................................................... 81
`2.0 PHYSICAL AND THERMAL PROPERTIES OF
`GROUP V CARBIDES ......................................................... 82
`2.1 Density and Melting Point.. .............................................. 82
`2.2 Thermal Properties .......................................................... 83
`3.0 ELECTRICAL PROPERTIES OF GROUP V CARBIDES ... 87
`4.0 MECHANICAL PROPERTIES OF GROUP V CARBIDES . 88
`5.0 CHEMICAL PROPERTIES OF GROUP V CARBIDES ....... 89
`5.1 Mutual Solubilities .......................................................... 89
`5.2 Chemical Properties ............................ ............................. 89
`6.0 CHARACTERISTICS AND PROPERTIES OF
`VANADIUM CARBIDE ....................................................... 89
`6.1 Summary ofProperties .................................................... 89
`6.2 Phase Diagram ................................................................ 91
`6.3 Summary of Fabrication Processes ................................... 92
`6.4 Summary of Applications and Industrial Importance ........ 92
`
`7.0 CHARACTERJS1
`NIOBIUM CARE:
`7.1 Summary ofP
`7.2 Phase Diagran
`7.3 Summary ofF:
`7.4 Summary of A
`8.0 CHARACTERJST
`TANTALUM CAl
`8.1 Summary ofP1
`8.2 Phase Diagram
`8.3 Summary of Fe
`8.4 Summary of At
`REFERENCES
`
`6 Carbides of Grou
`and Thngsten Ca1
`1.0 GENERAL CHA~
`GROUP VI CARBl
`l.l Common Featu1
`1.2 Refractory Cha1
`2.0 PHYSICAL AND 1
`GROUP VI CARBI
`2.1 Density and Me1
`2.2 Thermal Propert
`3.0 ELECTRICAL PRC
`4.0 MECHANICAL PRI
`5.0 CHEMICAL PROP!
`5.1 Mutual Solubilit
`5.2 Chemical Propel
`6.0 CHARACTERJSTI<
`CHROMIUM CARl
`6.1 Summary ofPro1
`6.2 Phase Diagram .
`6.3 Summary of Fab
`6.4 Summary of App
`7.0 CHARACTERISTIC
`MOLYBDENUM C1
`7.1 Summary ofPro(
`7.2 Phase Diagram ..
`7.3 Summary of Proc
`7.4 Summary of App
`
`

`

`UP IV CARBIDES ..... 68
`.................................... 68
`.................................... 68
`~TIES OF
`................................... 68
`.................................... 68
`................................... 72
`) .................................. 72
`striaJ Importance ........ 72
`.TIES OF
`................................... 73
`""""". """ "" .. " """"" 73
`................................... 74
`i .................................. 74
`striaJ Importance ........ 74
`TIES OF
`............................. ...... 76
`................................... 76
`................................... 77
`................................... 78
`;trial importance ....... 78
`.................................. 78
`
`1, Niobium and
`........................... 81
`
`.................................. 81
`RTIES OF
`.................................. 82
`.................................. 82
`.................................. 83
`)UP V CARBIDES ... 87
`:OUP V CARBIDES . 88
`IP V CARBIDES ....... 89
`...................... ............ 89
`.................................. 89
`riES OF
`.................................. 89
`.................................. 89
`.................................. 91
`... " ........... " .. " """ .... " 92
`trial Importance ........ 92
`
`' .
`
`Contents
`
`xiii
`
`7.0 CHARACTERISTICS AND PROPERTIES OF
`NIOBIUM CARBIDE ........................................................... 92
`7.1 Summary of Properties .................................................... 92
`7.2 Phase Diagram ................................................................ 92
`7.3 Summary of Fabrication Processes ................................... 95
`7.4 Summary of Applications and Industrial Importance ......... 95
`8.0 CHARACTERISTICS AND PROPERTIES OF
`TANTALUM CARBIDE ....................................................... 95
`8.1 Summary of Properties .................................................... 95
`8.2 Phase Diagram ........................................................... ..... 97
`8.3 Summary ofFabrication Processes ................................... 98
`8.4 Summary of Applications and Industrial Importance ........ 98
`REFERENCES
`..................................................................... 98
`
`6 Carbides of Group VI: Chromium, Molybdenum,
`and Tungsten Carbides ....................................... 100
`1.0 GENERAL CHARACTERISTICS OF
`GROUP VI CARBIDES ...................................................... 100
`1.1 Common Features of Group V1 <;::arbides ........... ............ 100
`l. 2 Refractory Characteristics .. . .. .. .. .. .. .. . .. .. . .. .. .. .. .. .. . .. .. .. .. . .. l 0 I
`2.0 PHYSICAL AND TIIERMAL PROPERTIES OF
`GROUP VI CARBIDES ...................................................... 101
`2. 1 Density and Melting Point.. ............................................ 102
`2.2 Thermal Properties ........................................................ 102
`3.0 ELECTRICAL PROPERTIES OF GROUP VI CARBIDES 104
`4.0 MECHANICAL PROPERTIES OF GROUP VI CARBIDES . 106
`5.0 CHEMICAL PROPERTIES OF GROUP VI CARBIDES ... 107
`5.1 Mutual Solubilities ........................................................ 107
`5.2 Chemical Properties ....................................................... 107
`6.0 CHARACTERISTICS AND PROPERTIES OF
`CHROMIUM CARBIDE ..................................................... I 07
`6.1 Summary of Properties ..................................... : ............ 107
`6.2 Phase Diagram .............................................................. 107
`6.3 Summary of Fabrication Processes ................................. 11 0
`6.4 Summary of Applications and Industrial Importance ...... 11 0
`7.0 CHARACTERISTICS AND PROPERTIES OF
`MOLYBDENUM CARBIDE .............................................. 110
`7.1 Summary of Properties .................................................. 110
`7.2 Phase Diagram .............................................................. 110
`7.3 Summary of Production Processes .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 112
`7.4 Summary of Applications and Industrial Importance ...... 112
`
`>;
`
`

`

`xiv Contents
`
`~-
`8.0 CHARACTERISTICS AND PROPERTIES OF
`TUNGSTEN CARBIDE ...................................................... 113
`8.1 Sununary of Properties .................................................. 113
`8.2 Phase Diagram .............................................................. 114
`8.3 Summary of Production Processes ................................. 115
`8.4 Summary of Applications and Industrial Importance ...... 116
`REFERENCES
`................................................................... 116
`
`7 Covalent Carbides: Structure and Composition .118
`1.0 GENERAL CHARACTERISTICS OF COVALENT
`CARBIDES
`................................................................... J J 8
`2 .0 ATOMIC STRUCTURE OF CARBON, BORON, AND
`SILI<;:ON
`................................................................... 119
`2.1 Electronic Configuration .... ............................................ 1 J 9
`2.2 Hybridized States .......................................................... 120
`3.0 STRUCTURE AND COMPOSITION OF
`SILICON CARBIDE ........................................................... 121
`3. 1 The Carbon-Silicon Crystal Unit Cell ............................. 121
`3.2 Covalent and Ionic Bonding ........................................... 122
`3.3 Beta Silicon Carbide ...................................................... 123
`3.4 Alpha Silicon Carbide and Polytypes ............................. 123
`3.5 Summary of Structural Data .......................................... 124
`3.6 Structural Correlation .................................................... 127
`3.7 Phase Diagram .............................................................. 127
`4.0 STRUCTURE AND COMPOSITION OF
`BORON CARBIDE .: ........................................................... 128
`4.1 The Boron Icosahedron .................................................. 128
`4.2 The Structure of Boron Carbide ..................................... 130
`4.3 Composition .................................................................. 132
`4.4 The Boron-Carbon Bond ................................................ 132
`4.5 Summary of Structural Data for Boron Carbide ............. 132
`4.6 Phase Diagram .............................................................. 134
`REFERENCES
`.............................................................. ..... 135
`
`8 Characteristics and Properties of Silicon Carbide
`and Boron Carbide .............................................. 137
`1.0 INTRODUCTION ............................................................... 137
`2.0 CHARACTERISTICS AND PROPERTIES OF
`SILICON CARBIDE ........................................................... 137
`2. 1 Historical Background and Present Status ...................... 137
`2.2 Summary ofProperties .................................................. 138
`
`3.0 CHARACTERISTII
`BORON CARBIDE
`3.1 Historical Back~
`3.2 Summary of Pro
`4.0 PHYSICAL AND T
`COVALENT CARE
`4.1 Discussion and I
`4.2 Physical Propert
`4.3 Thennal Propert
`5.0 ELECTRICAL ANI
`5.1 Electrical Propel
`5.2 Semiconductor I
`5 .3 Boron Carbide a
`6.0 MECHANICAL PR
`6.1 Property Variab.
`6.2 Summary of Me
`6.3 Strength
`6. 4 Hardness
`7.0 NUCLEARPROPE
`8.0 SUMMARY OF FA
`8. 1 Silicon Carbide .
`8.2 Boron Carbide ..
`9.0 SUMMARY OF AP
`INDUSTRIAL IMPI
`9. 1 Silicon Carbide .
`9.2 Boron Carbide ..
`REFERENCES
`
`9 The Refractory Ni
`1.0 INTRODUCTION ..
`2.0 GENERAL CHARA
`2.1 Definition and C
`2.2 Refractory Qual:
`3.0 FACTORS CONTR
`3.1 Nitride Formatio
`3.2 Nitride Fonnatio
`3.3 The Electronic B
`4.0 GENERAL CHARA
`4.1 Interstitial Nitrid
`4.2 Covalent Nitride.
`4.3 Intennediate Nit1
`4.4 Salt-Like Nitride
`REFERENCES
`
`

`

`~RTIES OF
`.................................... 113
`.................................... 113
`.................................... 114
`:s ................................. 115
`justrial Importance . . . . . . 116
`.................................... 116
`
`and Composition .118
`IF COVALENT
`.................................... 11 8
`)N, BORON, AND
`.................................... 119
`.................................... 119
`.................................... 120
`'-1 OF
`................................... 121
`Cell ............................. 121
`................................... 122
`................................... 123
`pes ............................. 123
`................................... 124
`................................... 127
`................................... 127
`~OF
`................................... 128
`................................... 128
`................................... 130
`................................... 132
`................................... 132
`toron Carbide ............. 132
`................... ................ 134
`................................... 135
`
`of Silicon Carbide
`, .......................... 13 7
`.................................. 137
`~TIES OF
`.................................. 137
`t Status ...................... 137
`.................................. 138
`
`Contents
`
`xv
`
`3.0 CHARACTERISTICS AND PROPERTIES OF
`BORON CARBIDE ............................................................. 142
`3.1 Historical Background and Present Status ...................... 142
`3.2 Summary of Properties .................................................. 142
`4.0 PHYSICAL AND THERMAL PROPERTIES OF THE
`COVALENT CARBIDES ................................................... 144
`4. 1 Discussion and Comparison .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. . .. .. . 144
`4.2 Physical Properties ........................................................ 145
`4.3 Thennal Properties ........................................................ 146
`5.0 ELECTRICAL AND SEMICONDUCTOR PROPERTIES . 147
`5 .I Electrical Properties ....................................................... 14 7
`5.2 Semiconductor Properties .............................................. 147
`5.3 Boron Carbide as a Thennoelectric Material .................. 149
`6.0 MECHANICAL PROPERTIES ........................................... 149
`6.1 Property Variables ......................................................... 149
`6.2 Summary of Mechanical Properties ................................ 149
`6.3 Strength
`............................................. : ..................... 149
`6.4 Hardness
`................................................................... 150
`7.0 NUCLEAR PROPERTIES ........... , ...................................... 151
`8.0 SUMMARY OF FABRJCATION PROCESSES ................. 151
`8. 1 Silicon Carbide ......................................................... ..... 151
`8.2 Boron Carbide ............................................................... 152
`9.0 SUMMARY OF APPLICATIONS AND
`INDUSTRIAL IMPORTANCE ........................................... 152
`9.1 SiliconCarbide .............................................................. l52
`9.2 Boron Carbide .......................................................... ..... 153
`................................................................... 154
`REFERENCES
`
`9 The Refractory Nitrides ..................................... 156
`1.0 INTRODUCTION ............................................................... 156
`2.0 GENERAL CHARACTERISTICS OF NITRIDES · ............. 156
`2. 1 Definition and Classification .......................................... 156
`2.2 Refractory Qualifications ............................................... 158
`3.0 FACTORS CONTROLLING NITRIDE FORMATION ...... 158
`3.1 Nitride Fonnation and Electronegativity ......................... 158
`3.2 Nitride Fonnation and Atom Size ..................... .............. 159
`3.3 The Electronic Bonding ofNitrides ................................ 159
`4.0 GENERAL CHARACTERISTICS OF NITRIDES ............. 159
`4.1 Interstitial Nitrides ......................................................... 159
`4.2 Covalent Nitrides .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. . 161
`4.3 lntennediate Nitrides ...................................................... 161
`4.4 Salt-Like Nitrides .......................................................... 161
`REFERENCES
`................................................................... 162
`
`

`

`I
`
`xvi Contents
`
`10 Interstitial Nitrides: Structure and Composition 163
`1.0 DEFINITION AND GENERAL CHARACTERISTICS OF
`INTERSTITIAL NITRIDES . . .. . . . . .. . ... .. . . . . ... . . . .. . .................. 163
`1. 1 Definition
`................................................... :. . . . . . . . . . . . . . . 163
`1.2 General Characteristics .................................................. 164
`2.0 ATOMIC STRUCTURE OF NITROGEN ........................... 165
`2.1 Nucleus and Electronic Configuration of
`(:
`the Nitrogen Atom . . . . . . . .. . . . . . . . . . . . . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
`2.2 Bonding and Hybridization ............................................ J 66
`3.0 ATOMIC STRUCTURE OF INTERSTITIAL NITRIDES .. 168
`3. 1 Atomic Radii Ratio ........................................................ 168
`3.2 Interstitial Sites ............ ................................ .................. 169
`4.0 COMPOSITION f.ND CRYSTALLINE STRUCTURE OF
`INTERSTITIAL NITRIDES ............................................... 169
`4. 1 Composition and Structure ............................................. 169
`4.2 Composition .................................................................. 171
`4.3 Summary of Characteristics ........................................... 172
`4.4 Metal-to-Nitride Structural Switching ............................ 172
`4.5 Density Considerations .................................................. 174
`5.0 ATOMIC BONDING OF INTERSTITIAL NITRIDES ....... 174
`5 .1 Overall Bonding Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7 4
`5.2 Thennal Properties Considerations ................................. 176
`5.3 Ionic Bonding and Electronegativity ............................... 179
`REFERENCES
`................................................................... 180
`.
`11 Interstitial Nitrides: Properties and General
`Characteristics .................................................... 181
`1.0 GENERAL PROPERTIES OF INTERSTITIAL NITRIDES 181
`2.0 PHYSICAL AND THERMAL PROPERTIES OF
`INTERSTITIAL NITRIDES ............................................... 181
`2.1 Composition and Stoichiometry ...................................... 182
`2.2 Density and Melting Point.. ............................................ 182
`2.3 Thennal Properties ......................................................... 183
`2.4 Thennal Conductivity .................................................... 184
`2.5 Thennal Expansion ........................................................ 185
`3.0 ELECTRICAL PROPERTIES OF INTERSTITIAL
`NITRIDES
`................................................................... 187
`4.0 MECHANlCAL PROPERTIES OF INTERSTITIAL
`NITRIDES
`................... ................................................ 188
`4. I Summary of Mechanical Properties ................................ 189
`4.2 Hardness
`................................................................... 189
`
`5.0 CHEMICAL PRO
`5 .1 Mutual Solub
`5 .2 Chemical Pro1
`6.0 TITANIUM NITI
`6 .1 Summary ofi
`6.2 Isomorphism.
`6.3 Phase Diagrru
`6.4 Summary ofl
`6.5 Sununary of I
`7.0 ZIRCONIUM Nf
`7.1 Summary off
`7 .2 Isomorphism .
`7 .3 Phase Diagrru
`7.4 Summary of I
`7.5 Summary of )
`8.0 HAFNIUM NITR
`8.1 Summary ofF
`8.2 Isomorphism.
`8 .3 Phase Diagrru
`8 .4 Summary of f
`8.5 Summary oU
`9.0 VANADIUM Nil
`9.1 Summary of P
`9'.2 Isomorphism.
`9.3 Phase Diagrar
`9.4 Summary ofF
`9•.5 Summary of P
`10.0 NIOBIUM NITRI
`10.1 Summary ofF
`I 0.2 Isomorphism.
`10.3 Phase Diagran
`10.4 Summary of F
`10.5 Summary of .A
`11.0 TANTALUM Nil
`11 . I Summary of P
`1 I .2 Isomorphism.
`11 .3 Phase Diagran
`11 .4 Summary ofF
`1 I .5 Summary of A
`REFERENCES
`
`

`

`e and Composition 163
`MRACTERISTICS OF
`...................................... 163
`······································ 163
`...................................... 164
`OGEN ........................... 165
`ration of
`······································ 165
`...................................... 166
`RSTITIAL NITRIDES .. 168
`...................................... 168
`..................................... 169'
`J NE STRUCTURE