Foreword xiii
Acknowledgments xv
General Abbreviations xvii
1 Introduction 1
1.1 Importance of Transparent Ceramics: The Book’s Rationale Topic and Aims 1
1.2 Factors Determining the Overall Worth of Transparent Ceramics 2
1.2.1 Technical Characteristics 2
1.2.2 Fabrication and Characterization Costs 3
1.2.3 Overview of Worth 3
1.3 Spectral Domain for Ceramics High Transmission Targeted in This Book 3
1.3.1 High Transmission Spectral Domain 3
1.3.2 Electromagnetic Radiation/Solid Interaction in the Vicinity of the Transparency Domain 4
1.4 Definition of Transparency Levels 4
1.5 Evolution of Transmissive Ability Along the Ceramics Development History 6
1.5.1 Ceramics with Transparency Conferred by Glassy Phases 6
1.5.2 The First Fully Crystalline Transparent Ceramic 7
1.5.3 A Brief Progress History of All-Crystalline Transparent Ceramics 8
2 Electromagnetic Radiation: Interaction with Matter 11
2.1 Electromagnetic Radiation: Phenomenology and Characterizing Parameters 11
2.2 Interference and Polarization 13
2.3 Main Processes which Disturb Electromagnetic Radiation After Incidence on a Solid 13
2.3.1 Refraction 14
2.3.2 Reflection 17
2.3.3 Birefringence 20
2.3.4 Scattering 22
2.3.4.1 Scattering by Pores 22
2.3.4.2 Scattering Owed to Birefringence 24
2.3.5 Absorption 27
2.3.5.1 Transition Metal and Rare-Earth Cations in Transparent Ceramic Hosts 27
2.3.5.2 Absorption Spectra of Metal and Rare-Earth Cations Located in TC Hosts 28
2.3.5.2.1 Transition Metal and Rare-Earth Cations’ Electronic Spectra: Theoretical Basis 29
2.3.5.2.1.1 Electronic States of a Cation in Free Space 29
2.3.5.2.2 Absorption Spectra of Transition Metal and Rare-Earth Cations: Examples 50
2.3.5.2.2.1 The Considered Solid Hosts 50
2.4 Physical Processes Controlling Light Absorption in the Optical Window Vicinity 54
2.4.1 High Photon Energy Window Cutoff: Ultraviolet Light Absorption in Solids 54
2.4.2 Low Photon Energy Window Cutoff: Infrared Light Absorption in Solids 58
2.4.2.1 Molecular Vibrations 58
2.4.2.2 Solid Vibrations 59
2.4.2.3 Acoustic Modes 61
2.4.2.4 Optical Modes 62
2.5 Thermal Emissivity 66
2.6 Color of Solids 67
2.6.1 Quantitative Specification of Color 67
2.6.2 Coloration Mechanisms: Coloration Based on Conductive Colloids 71
3 Ceramics Engineering: Aspects Specific to Those Transparent 73
3.1 Processing 73
3.1.1 List of Main Processing Approaches 73
3.1.2 Powder Compacts Sintering 73
3.1.2.1 Configuration Requirements for High Green Body Sinterability: Factors of Influence 73
3.1.2.2 Powder Processing and Green-Body Forming 77
3.1.2.2.1 Agglomerates 77
3.1.2.2.2 Powder Processing 80
3.1.2.2.3 Forming Techniques 81
3.1.2.2.3.1 Press Forming 81
3.1.2.2.3.2 Liquid-Suspensions Based Forming 84
3.1.2.2.3.3 Slip-Casting Under Strong Magnetic Fields 86
3.1.2.2.3.4 Gravitational Deposition, Centrifugal-Casting, and Filter-Pressing 88
3.1.2.3 Sintering 89
3.1.2.3.1 Low Relevancy of Average Pore Size 89
3.1.2.3.2 Pore Size Distribution Dynamics During Sintering 89
3.1.2.3.3 Grain Growth 93
3.1.2.3.4 Methods for Pores Closure Rate Increase 93
3.1.2.3.4.1 Liquid Assisted Sintering 94
3.1.2.3.4.2 Pressure Assisted Sintering 94
3.1.2.3.4.3 Sintering Under Electromagnetic Radiation 96
3.1.2.3.4.4 Sintering Slip-Cast Specimens Under Magnetic Field 97
3.1.2.3.4.5 Reaction-Preceded Sintering 97
3.1.2.3.4.6 Use of Sintering Aids 98
3.1.3 Bulk Chemical Vapor Deposition (CVD) 98
3.1.4 Glass-Ceramics Fabrication by Controlled Glass Crystallization 98
3.1.4.1 Introduction 98
3.1.4.2 Glass Crystallization: Basic Theory 100
3.1.4.2.1 Nucleation 100
3.1.4.2.2 Crystal Growth 102
3.1.4.2.3 Phase Separation in Glass 102
3.1.4.2.4 Crystal Morphologies 103
3.1.4.3 Requirements for the Obtainment of Performant Glass-Ceramics 103
3.1.4.3.1 Nucleators 103
3.1.4.4 Influence of Controlled Glass Crystallization on Optical Transmission 104
3.1.4.4.1 Full Crystallization 105
3.1.5 Bulk Sol–Gel 105
3.1.6 Polycrystalline to Single Crystal Conversion via Solid-State Processes 107
3.1.7 Transparency Conferred to Non-cubic Materials by Limited Lattice Disordering 109
3.1.8 Transparent Non-cubic Nanoceramics 109
3.1.9 Grinding and Polishing 109
3.2 Characterization 111
3.2.1 Characterization of Particles, Slurries, Granules, and Green Bodies Relevant in Some Transparent Ceramics Fabrication 111
3.2.1.1 Powder Characterization 112
3.2.1.2 Granules Measurement and Slurry Characterization 113
3.2.1.3 Green-Body Characterization 114
3.2.2 Scatters Topology Illustration 115
3.2.2.1 Laser-Scattering Tomography (LST) 116
3.2.3 Discrimination Between Translucency and High Transmission Level 116
3.2.4 Bulk Density Determination from Optical Transmission Data 117
3.2.5 Lattice Irregularities: Grain Boundaries, Cations Segregation, Inversion 118
3.2.6 Parasitic Radiation Absorbers’ Identification and Spectral Characterization 123
3.2.6.1 Absorption by Native Defects of Transparent Hosts 123
3.2.7 Detection of ppm Impurity Concentration Levels 124
3.2.8 Mechanical Issues for Windows and Optical Components 126
4 Materials and Their Processing 131
4.1 Introduction 131
4.1.1 General 131
4.1.2 List of Materials and Their Properties 131
4.2 Principal Materials Description 131
4.2.1 Mg and Zn Spinels 131
4.2.1.1 Mg-Spinel 131
4.2.1.1.1 Structure 131
4.2.1.1.2 Fabrication 136
4.2.1.1.3 Properties of Spinel 146
4.2.1.2 Zn-Spinel 152
4.2.2 γ-Al-oxynitride 152
4.2.2.1 Composition and Structure 152
4.2.2.2 Processing 154
4.2.2.2.1 Fabrication Approaches 154
4.2.2.2.2 Powder Synthesis 155
4.2.2.2.3 Green Parts Forming. Sintering 155
4.2.2.3 Characteristics of Densified Parts 156
4.2.3 Transparent and Translucent Alumina 157
4.2.3.1 Structure 158
4.2.3.1.1 Utility of T-PCA 158
4.2.3.2 Processing of Transparent Ceramic Alumina 159
4.2.3.2.1 Raw Materials 159
4.2.3.2.2 Processing 159
4.2.3.3 Properties of Transparent Alumina 163
4.2.4 Transparent Magnesia and Calcia 163
4.2.4.1 Structure 164
4.2.4.2 Raw Materials and Processing 165
4.2.4.3 Properties 167
4.2.4.4 Transparent Calcium Oxide 169
4.2.5 Transparent YAG and Other Garnets 169
4.2.5.1 Structure, Processing, and Properties of YAG 170
4.2.5.1.1 Processing 170
4.2.5.1.2 Properties of YAG 174
4.2.5.2 LuAG 177
4.2.5.3 Garnets Based on Tb 178
4.2.5.4 Garnets Based on Ga 179
4.2.5.5 Other Materials Usable for Magneto-Optical Components 179
4.2.6 Transparent Yttria and Other Sesquioxides 180
4.2.6.1 Structure of Y2O3 180
4.2.6.2 Processing of Y2O3 181
4.2.6.2.1 Y2O3 Powders 181
4.2.6.2.2 Processing Approaches 181
4.2.6.2.3 Discussion of Processing 185
4.2.6.3 Properties of Y2O3 187
4.2.6.4 Other Sesquioxides with Bixbyite Lattice 187
4.2.6.4.1 Sc2O3 188
4.2.6.4.2 Lu2O3 189
4.2.7 Transparent Zirconia 190
4.2.7.1 Structure: Polymorphism, Effect of Alloying 190
4.2.7.2 Processing–Transparency Correlation in Cubic Zirconia Fabrication 192
4.2.7.2.1 Zirconia Powders 192
4.2.7.2.2 Forming and Sintering 193
4.2.7.3 Properties 194
4.2.7.3.1 Density of Zirconias 194
4.2.7.4 Types of Transparent Zirconia 195
4.2.7.4.1 TZPs 195
4.2.7.4.2 Cubic ZrO2 195
4.2.7.4.3 Monoclinic Zirconia 196
4.2.7.4.4 Electronic Absorption 197
4.2.8 Transparent Metal Fluoride Ceramics 198
4.2.8.1 Crystallographic Structure 199
4.2.8.2 Processing of Transparent-Calcium Fluoride 199
4.2.8.3 Properties 200
4.2.9 Transparent Chalcogenides 201
4.2.9.1 Composition and Structure 201
4.2.9.2 Processing 201
4.2.9.3 Properties 203
4.2.10 Ferroelectrics 203
4.2.10.1 Ferroelectrics with Perovskite-Type Lattice 203
4.2.10.2 PLZTs: Fabrication and Properties 204
4.2.10.2.1 Electro-optic Properties of PLZTs 207
4.2.10.3 Other Perovskites Including Pb 207
4.2.10.4 Perovskites Free of Pb 208
4.2.10.4.1 Ba Metatitanate 208
4.2.10.4.2 Materials Based on the Potassium Niobate-sodium Niobate System 209
4.2.11 Transparent Glass-Ceramics 210
4.2.11.1 Transparent Glass Ceramics Based on Stuffed β-Quartz Solid Solutions 210
4.2.11.2 Transparent Glass Ceramics Based on Crystals Having a Spinel-Type Lattice 212
4.2.11.3 Mullite-Based Transparent Glass-Ceramics 213
4.2.11.4 Other Transparent Glass-Ceramics Derived from Polinary Oxide Systems 214
4.2.11.5 Oxyfluoride Matrix Transparent Glass-Ceramics 214
4.2.11.6 Transparent Glass-Ceramics Including Very High Crystalline Phase Concentration 216
4.2.11.6.1 Materials of Extreme Hardness (Al2O3–La2O3, ZrO2) 216
4.2.11.6.2 TGCs of High Crystallinity Including Na3Ca Silicates 216
4.2.11.6.3 Materials for Scintillators 217
4.2.11.7 Pyroelectric and Ferroelectric Transparent Glass-Ceramics 217
4.2.12 Cubic Boron Nitride 222
4.2.13 Ultrahard Transparent Polycrystalline Diamond Parts 222
4.2.13.1 Structure 222
4.2.13.2 Fabrication 224
4.2.13.3 Properties 225
4.2.14 Galium Phosphide (GaP) 225
4.2.15 Transparent Silicon Carbide and Nitride and Aluminium Oxynitride 226
5 TC Applications 227
5.1 General Aspects 227
5.2 Brief Description of Main Applications 227
5.2.1 Envelopes for Lighting Devices 227
5.2.2 Transparent Armor Including Ceramic Layers 229
5.2.2.1 Armor: General Aspects 229
5.2.2.1.1 The Threats Armor Has to Defeat (Projectiles) 229
5.2.2.1.2 The Role of Armor 230
5.2.2.1.3 Processes Generated by the Impact of a Projectile on a Ceramic Strike-Face (Small Arm Launchers) 231
5.2.2.1.4 Final State of the Projectile/Armor Impact Event Participants 234
5.2.2.1.4.1 Armor Performance Descriptors 235
5.2.2.1.5 Characteristics which Influence Armor Performance 236
5.2.2.1.6 Ceramic Armor Study and Design 236
5.2.2.2 Specifics of the Transparent-Ceramic Based Armor 239
5.2.2.3 Materials for Transparent Armor 243
5.2.2.3.1 Ceramics 243
5.2.2.3.2 Single Crystals 245
5.2.2.3.3 Glass-Ceramics 246
5.2.2.3.4 Glasses 248
5.2.2.4 Examples of Transparent Ceramics Armor Applications 248
5.2.3 Infrared Windows 249
5.2.3.1 The Infrared Region 249
5.2.3.2 Background Regarding Heavy Duty Windows 249
5.2.3.2.1 Threats to Missile IR Domes: Material Characteristics Relevant for Their Protection 249
5.2.3.2.1.1 Impact of Particulates (Erosion) 249
5.2.3.2.1.2 Thermal Shock 250
5.2.3.3 Applications of infrared transparent ceramics 251
5.2.3.3.1 Missile Domes and Windows for Aircraft-Sensor Protection 251
5.2.3.3.2 Laser Windows: Igniters, Cutting Tools, LIDARs 251
5.2.3.3.2.1 Igniters 251
5.2.3.3.2.2 LIDAR-Windows 252
5.2.3.3.3 Windows for Vacuum Systems 252
5.2.3.4 Ceramic Materials Optimal for the Various IR Windows Applications 252
5.2.3.4.1 Competitor Materials: Glasses and Single Crystals 253
5.2.3.4.2 Glasses 253
5.2.3.4.3 Single Crystals 253
5.2.3.4.4 Sapphire 254
5.2.3.4.5 Crystals for the 8–12 μm Window 254
5.2.3.5 Radomes 254
5.2.4 Transparent Ceramics for Design, Decorative Use, and Jewelry 254
5.2.5 Components of Imaging Optic Devices (LENSES) 258
5.2.6 Dental Ceramics 260
5.2.7 Applications of Transparent Ferroelectric and Pyroelectric Ceramics 262
5.2.7.1 Flash Goggles 263
5.2.7.2 Color Filter 263
5.2.7.3 Stereo Viewing Device 264
5.2.7.4 Applications of Second-Generation (Non-PLZT) Ferroelectric Ceramics 265
5.2.8 Applications of Ceramics with Magnetic Properties 265
5.2.9 Products Based on Ceramic Doped with Transition and/or Rare-Earth Cations 267
5.2.9.1 Gain Media for Solid-State Lasers 267
5.2.9.1.1 Lasers: Definition and Functioning Mechanisms 267
5.2.9.1.1.1 Lasing Mechanisms 267
5.2.9.1.2 Laser Systems Efficiency: Characterizing Parameters 277
5.2.9.1.3 Laser Oscillators and Amplifiers 277
5.2.9.1.4 Device Operation Related Improvements Allowing Increase of Ceramic Lasers Performance 278
5.2.9.1.4.1 Diode Lasers as Pumping Sources 278
5.2.9.1.4.2 Cryogenic Operation 278
5.2.9.1.4.3 Cavity-Loss Control 279
5.2.9.1.4.4 Laser Output Signal Manipulation 280
5.2.9.1.4.5 Lasing Device Configuration Optimization 281
5.2.9.1.4.6 ThinZag Configuration 281
5.2.9.1.4.7 Virtual Point Source Pumping 282
5.2.9.1.5 Ceramic Gain Media (Host+Lasant Ion) Improvements 283
5.2.9.1.5.1 The Hosts 283
5.2.9.1.5.2 Principal Lasing Cations Operating in Ceramic Hosts 289
5.2.9.1.6 Applications of Ceramic Lasers 299
5.2.9.1.6.1 Materials Working 299
5.2.9.1.6.2 Laser Weapons 300
5.2.9.1.6.3 Combustion Ignitors: Cars and Guns 300
5.2.9.1.6.4 Other Applications 300
5.2.9.2 Q-switches 303
5.2.9.2.1 General 303
5.2.9.2.2 Transition Metal Cations Usable for Switching 304
5.2.9.2.2.1 Co2+ 304
5.2.9.2.2.2 Cr4+,5+ 306
5.2.9.2.2.3 V3+ 308
5.2.9.2.2.4 Cr2+ (d4), Fe2+ (d6) 309
5.2.9.3 Ceramic Phosphors for Solid State Lighting Systems 309
5.2.9.3.1 Artificial Light Sources: General Considerations 309
5.2.9.3.1.1 Conventional Light Sources Powered by Electricity 310
5.2.9.3.1.2 Incandescent Lamps 311
5.2.9.3.1.3 Discharge Lamps 311
5.2.9.3.1.4 Fluorescent Lamps 313
5.2.9.3.1.5 Solid-State Lighting Sources 313
5.2.9.3.2 Transparent Bulk Ceramics Based Phosphors for Light Sources Based on LEDs 314
5.2.9.3.2.1 Ce3+:YAG and Ce3+, RE3+:YAG Phosphors 314
5.2.9.3.2.2 Bathochrome Moving (Redshifting) of Ce3+ Emission by YAG Lattice Straining 318
5.2.9.3.2.3 Summary of SSLSs 321
5.2.9.4 Scintillators 321
6 Future Developments 325
7 Conclusions 327
References 329
Index 357
