Cellular ceramics : structure, manufacturing, properties and applications /

Foreword 7
Contents 9
Preface 21
List of Contributors 23
Part 1 Introduction 29
1.1 Cellular Solids \u2013 Scaling of Properties 31
1.1.1 Introduction 31
1.1.2 Cellular or \u201cLattice\u201d Materials 32
1.1.3 Bending-Dominated Structures 33
1.1.3.1 Mechanical Properties 34
1.1.3.2 Thermal Properties 37
1.1.3.3 Electrical Properties 38
1.1.4 Maxwell\u2019s Stability Criterion 38
1.1.5 Stretch-Dominated Structures 40
1.1.6 Summary 44
1.2 Liquid Foams \u2013 Precursors for Solid Foams 46
1.2.1 The Structure of a Liquid Foam 46
1.2.2 The Elements of Liquid Foam Structure 49
1.2.3 Real Liquid Foams 52
1.2.4 Quasistatic Processes 52
1.2.5 Beyond Quasistatics 54
1.2.6 Summary 56
Part 2 Manufacturing 59
2.1 Ceramic Foams 61
2.1.1 Introduction 61
2.1.2 Replication Techniques 62
2.1.2.1 Slurry Coating and Combustion of Polymer Foams 62
2.1.2.2 Pyrolysis and CVD Coating of Polymer Foams 66
2.1.2.3 Structure of Reticulated Ceramics 67
2.1.3 Foaming Techniques 70
2.1.3.1 Incorporation of an External Gas Phase 70
2.1.3.2 In Situ Gas Evolution 74
2.1.3.3 Gelation 77
2.1.3.4 Ceramic Foam Structure 79
2.1.4 Other Techniques 80
2.1.6 Summary 82
2.2 Honeycombs 85
2.2.1 Introduction 85
2.2.2 Forming the Honeycomb Geometry 85
2.2.2.1 Background 85
2.2.2.2 Honeycomb Extrusion Die 87
2.2.2.3 Nonextrusion Fabrication Processes 90
2.2.3 Composition 91
2.2.3.1 Paste 91
2.2.3.2 Mixing 92
2.2.3.3 The Binder 93
2.2.4 Thermal Processing 94
2.2.4.1 Diffusion: Drying and Debinding 94
2.2.4.2 Melt Manipulation 95
2.2.4.3 Sinter Shrinkage Manipulation 96
2.2.5 Post-Extrusion Forming 97
2.2.5.1 Reduction Extrusion 98
2.2.5.2 Hot Draw Reduction 101
2.2.6 Summary 110
2.3 Three-Dimensional Periodic Structures 115
2.3.1 Introduction 115
2.3.2 Direct-Write Assembly 115
2.3.3 Colloidal Inks 117
2.3.4 Ink Flow during Deposition 119
2.3.5 Shape Evolution of Spanning Filaments 122
2.3.6 Direct-Write Assembly of 3D Periodic Structures 124
2.3.7 Summary 127
2.4 Connected Fibers: Fiber Felts and Mats 129
2.4.1 Introduction 129
2.4.2 Oxide Fibers 130
2.4.2.1 Melt-Blown Silica Fibers 130
2.4.2.2 Blown Alumina\u2013Silica Fibers 132
2.4.2.3 Drawn Alumina\u2013Borosilicate Fibers 133
2.4.3 Fiber Product Forms 134
2.4.3.1 Continuous Monofilaments 135
2.4.3.2 Fiber Mat 135
2.4.3.3 Bulk Fiber 137
2.4.4 High-Performance Insulation for Space Vehicles 137
2.4.4.1 Rigid Space Shuttle Tiles 138
2.4.4.2 Flexible Insulation Blankets 144
2.4.4.3 Innovations in Thermal Protection Systems 145
2.4.5 Summary 148
2.5 Microcellular Ceramics from Wood 150
2.5.1 Introduction 150
2.5.2 Fabrication of Porous Biocarbon Templates 152
2.5.3 Preparation of Carbide-Based Biomorphous Ceramics 154
2.5.3.1 Processing by Silicon-Melt Infiltration 155
2.5.3.2 Gas-Phase Processing 157
2.5.4 Preparation of Oxide-Based Biomorphous Ceramics 159
2.5.5 Summary 162
2.6 Carbon Foams 165
2.6.1 Introduction 165
2.6.2 History 165
2.6.3 Terminology 166
2.6.3.1 Carbon 167
2.6.3.2 Graphite 167
2.6.3.3 Graphitization 167
2.6.3.4 Foam 168
2.6.4 Foaming Processes 169
2.6.4.1 Thermosetting Precursors 169
2.6.4.2 Thermoplastic Precursors 172
2.6.5 Properties of Carbon and Graphite Foam 181
2.6.6 Summary 183
2.7 Glass Foams 186
2.7.1 Introduction 186
2.7.2 Historical Background 186
2.7.3 Starting Glasses 188
2.7.4 Modern Foaming Process 189
2.7.4.1 Initial Particle Size of the Glass and the Foaming Agent 189
2.7.4.2 Heating Rate 191
2.7.4.3 Foaming Temperature 192
2.7.4.4 Heat-Treatment Time 192
2.7.4.5 Chemical Dissolved Oxygen 192
2.7.4.6 Cooling Rate 193
2.7.5 Foaming Agents 194
2.7.5.1 Foaming by Thermal Decomposition 194
2.7.5.2 Foaming by Reaction 195
2.7.6 Glass Foam Products 198
2.7.7 Alternative Processes and Products 199
2.7.7.1 Foams from Evaporation of Metals 200
2.7.7.2 High-Silica Foams from Phase-Separating Glasses 200
2.7.7.3 Microwave Heating 200
2.7.7.4 Glass Foam from Silica Gel 201
2.7.7.5 High-Density Glass Foam 201
2.7.7.6 Partially Crystallized Glass Foam 201
2.7.7.7 Foaming of CRT Glasses 202
2.7.8 Summary 203
2.8 Hollow Spheres 205
2.8.1 Introduction 205
2.8.2 Processing Methods 206
2.8.2.1 Sacrificial-Core Method 206
2.8.2.2 Layer-by-Layer Deposition 207
2.8.2.3 Emulsion/Sol\u2013Gel Method 210
2.8.2.4 Spray and Coaxial-Nozzle Techniques 213
2.8.2.5 Reaction-Based and Other Methods 216
2.8.3 Cellular Ceramics from Hollow Spheres (Syntactic Foams) 216
2.8.4 Properties 216
2.8.5 Applications 217
2.8.6 Summary 218
2.9 Cellular Concrete 221
2.9.1 Introduction 221
2.9.2 Types of Cellular Concrete 222
2.9.2.1 Low Temperature Cured Cellular Concrete 223
2.9.2.2 Autoclave-Cured Cellular Concrete 225
2.9.3 Per-Capita Consumption 226
2.9.4 Overview of Cellular Concrete 227
2.9.4.1 The Gas Phase 227
2.9.4.2 The Matrix Phase 228
2.9.5 Portland Cement 234
2.9.5.1 History 235
2.9.5.2 Fabrication of Portland Cement 235
2.9.5.3 Hydration 236
2.9.6 Properties of Calcium Silicate Hydrate in Cellular Concretes 239
2.9.6.1 Cast-in-Place or Precast Cellular Concrete 240
2.9.6.2 Autoclaved Aerated Concrete (AAC) 242
2.9.7 Durability of Cellular Concrete 247
2.9.8 Summary 249
Part 3 Structure 253
3.1 Characterization of Structure and Morphology 255
3.1.1 Introduction and Theoretical Background 255
3.1.1.1 The Importance of Foam Structure Characterization 255
3.1.1.2 Structure-Dependent Properties 256
3.1.1.3 Parameters Describing the Structure of the Foams 258
3.1.2 Characterization of Foam Pore Structure 260
3.1.2.1 Sample Preparation 261
3.1.2.2 Characterization Methods 261
3.1.2.3 Comparison of Methods 290
3.1.3 Summary 291
3.2 Modeling Structure\u2013Property Relationships in Random Cellular Materials 295
3.2.1 Introduction 295
3.2.2 Theoretical Structure\u2013Property Relations 296
3.2.3 Modeling and Measuring Structure 301
3.2.4 Computational Structure\u2013Property Relations 308
3.2.5 Summary 313
Part 4 Properties 317
4.1 Mechanical Properties 319
4.1.1 Introduction 319
4.1.2 Modeling the Porosity Dependence of Mechanical Properties of Cellular Ceramics 320
4.1.2.1 Earlier Models 320
4.1.2.2 Gibson\u2013Ashby Models 322
4.1.2.3 Minimum Solid Area (MSA) Models 323
4.1.2.4 Computer Models 326
4.1.3 Porosity Effects on Mechanical Properties of Cellular Ceramics 327
4.1.3.1 Honeycomb Structures 327
4.1.3.2 Foams and Related Structures 329
4.1.4 Discussion 335
4.1.4.1 Measurement\u2013Characterization Issues 335
4.1.4.2 Impact of Fabrication on Microstructure 336
4.1.4.3 Porosity\u2013Property Trade-Offs 337
4.1.5 Summary 338
4.2 Permeability 341
4.2.1 Introduction 341
4.2.2 Description of Permeability 341
4.2.3 Experimental Evaluation of Permeability 343
4.2.4 Models for Predicting Permeability 345
4.2.4.1 Granular Media 346
4.2.4.2 Fibrous Media 348
4.2.4.3 Cellular Media 349
4.2.5 Viscous and Inertial Flow Regimes in Porous Media 359
4.2.6 Summary 366
4.3 Thermal Properties 370
4.3.1 Introduction 370
4.3.2 Thermal Conductivity 370
4.3.2.1 Experimental Methods to Determine the Effective Thermal Conductivity without Flow 373
4.3.2.2 Method to Determine the Effective Thermal Conductivity with Flow 376
4.3.3 Specific Heat Capacity 378
4.3.4 Thermal Shock 378
4.3.5 Volumetric Convective Heat Transfer 380
4.3.5.1 Nusselt/Reynold Correlations and Comparison with Theoretical Data 382
4.3.6 Summary 387
4.4 Electrical Properties 389
4.4.1 Introduction and Fundamentals 389
4.4.2 Specific Aspects of Electrical Properties of Cellular Solids 394
4.4.2.1 Honeycombs 395
4.4.2.2 Biomimetic Ceramic Structures 396
4.4.2.3 Ceramic Foams 397
4.4.2.4 Ceramic Fibers 402
4.4.3 Electrical Applications of Cellular Ceramics 404
4.4.3.1 Foam Ceramic Heaters 404
4.4.3.2 Electrically Conductive Honeycombs 406
4.4.4 Summary 407
4.5 Acoustic Properties 409
4.5.1 Introduction 409
4.5.2 Acoustic Propagation 409
4.5.2.1 Linearized Equations of Motion 409
4.5.2.2 Wave Equation 410
4.5.2.3 Relationships between Acoustic Parameters under Inviscid Conditions 411
4.5.2.4 Acoustic Energy 412
4.5.3 Acoustic Properties 412
4.5.3.1 Acoustic Impedance and Admittance 412
4.5.3.2 Acoustic Wavenumber 414
4.5.3.3 Reflection Coefficient, Transmission Coefficient, and Transmission Loss 414
4.5.3.4 Absorption Coefficient 415
4.5.4 Experimental Techniques 415
4.5.4.1 Moving-Microphone Technique 415
4.5.4.2 Two- and Four-Microphone Techniques 416
4.5.5 Empirical Models 417
4.5.6 Theoretical Models 418
4.5.6.1 Viscous Attenuation in Channels (Rayleigh\u2019s Model) 418
4.5.6.2 Acoustic Damping by an Array of Elements Perpendicular to the Propagation Direction 419
4.5.6.3 Generalized Models 420
4.5.6.4 Complex Viscosity and Complex Density Models 420
4.5.6.5 Direct Models 421
4.5.6.6 Biot\u2019s Model 423
4.5.6.7 Lambert\u2019s Model 424
4.5.7 Acoustic Applications of Cellular Ceramics 425
4.5.8 Summary 426
Part 5 Applications 429
5.1 Liquid Metal Filtration 431
5.1.1 Introduction 431
5.1.2 Theory of Molten-Metal Filtration 432
5.1.3 Commercial Applications 436
5.1.3.1 Aluminum 436
5.1.3.2 Iron Foundry 438
5.1.3.3 Steel 440
5.1.4 Summary 442
5.2 Gas (Particulate) Filtration 444
5.2.1 Introduction 444
5.2.2 Properties of (Catalytic) Cellular Filters 445
5.2.3 Applications 446
5.2.3.1 Diesel Particulate Abatement 446
5.2.3.2 Abatement of Gaseous Pollutants and Fly-Ash 456
5.2.4 Modeling 461
5.2.5 Summary 464
5.3 Kiln Furnitures 467
5.3.1 Introduction 467
5.3.2 Application of Ceramic Foam to Kiln Furniture 469
5.3.2.1 Longer Life 469
5.3.2.2 More Uniform Atmosphere Surrounding the Fired Ware 474
5.3.2.3 Reduction of Frictional Forces during Shrinkage 475
5.3.2.4 Chemical Inertness 475
5.3.2.5 Cost Benefits 476
5.3.3 Manufacture of Kiln Furniture 477
5.3.3.1 Foam Replication Process 477
5.3.3.2 Foams Manufactured by using Fugitive Pore Formers 479
5.3.4 Summary 480
5.4 Heterogeneously Catalyzed Processes with Porous Cellular Ceramic Monoliths 482
5.4.1 Introduction 482
5.4.2 Making Catalysts from Ceramic Monoliths 483
5.4.2.1 Enlargement of Surface Area and Preparation for Catalyst Loading 484
5.4.2.2 Loading with Catalytically Active Components and Activation 485
5.4.2.3 Zeolite Coating: A Combination of High Surface Area and Catalytic Activity 486
5.4.3 Some Catalytic Processes with Honeycomb Catalysts 489
5.4.3.1 Automotive Catalysts 489
5.4.3.2 Diesel Engine Catalysts 492
5.4.3.3 Catalytic Combustion for Gas Turbines 493
5.4.3.4 Applications of Honeycomb Catalysts for Other Gas Phase Reactions 493
5.4.3.5 Honeycomb Catalysts for Gas/Liquid-Phase Reactions 495
5.4.3.6 Other Research Applications of Honeycomb Catalysts 500
5.4.4 Catalytic Processes with Ceramic Foam Catalysts 501
5.4.4.1 Improvement of Technical Processes for Base Chemicals Production 502
5.4.4.2 Hydrogen Liberation from Liquid Precursors/Hydrogen Cleaning for Fuel Cell Applications 503
5.4.4.3 Automotive and Indoor Exhaust Gas Cleaning 504
5.4.4.4 Catalytic Combustion in Porous Burners 507
5.4.5 Summary 507
5.5 Porous Burners 512
5.5.1 Introduction 512
5.5.2 Flame Stabilization of Premixed Combustion Processes in Porous Burners 514
5.5.2.1 Flame Stabilization by Unsteady Operation 516
5.5.2.2 Flame Stabilization under Steady Operation by Convection and Cooling 517
5.5.2.3 Flame Stabilization under Steady Operation by Thermal Quenching 518
5.5.2.4 Diffusive Mass-Transport Effects on Flame Stabilization 520
5.5.3 Catalytic Radiant Surface Burners 521
5.5.4 Radiant Surface Burners 522
5.5.5 Volumetric Porous Burners with Flame Stabilization by Thermal Quenching 523
5.5.5.1 Materials and Shapes for Porous-Medium Burners 524
5.5.5.2 Applications of Volumetric Porous Burners 526
5.5.6 Summary 534
5.6 Acoustic Transfer in Ceramic Surface Burners 537
5.6.1 Introduction 537
5.6.2 Acoustic Transfer 539
5.6.3 Analytical Model 540
5.6.4 Acoustic Transfer Coefficient for Realistic Porous Ceramics 542
5.6.4.1 Numerical Results 543
5.6.4.2 Measurements 546
5.6.5 Summary 549
5.7 Solar Radiation Conversion 551
5.7.1 Introduction 551
5.7.2 The Volumetric Absorber Principle 553
5.7.3 Optical, Thermodynamic, and Fluid-Mechanical Requirements of Cellular Ceramics for Solar Energy Conversion 554
5.7.4 Examples of Cellular Ceramics Used as Volumetric Absorbers 560
5.7.4.1 Extruded Silicon Carbide Catalyst Supports 560
5.7.4.2 Ceramic Foams 561
5.7.4.3 SiC Fiber Mesh 562
5.7.4.4 Screen-Printed Absorbers (Direct-Typing Process) 563
5.7.4.5 Material Combinations 564
5.7.5 Absorber Tests 564
5.7.6 Physical Restrictions of Volumetric Absorbers and Flow Phenomena in cellular ceramics 567
5.7.6.1 Experimental Determination of Nonstable Flow 572
5.7.7 Summary 573
5.8 Biomedical Applications: Tissue Engineering 575
5.8.1 Introduction 575
5.8.2 Regenerative Medicine and Biomaterials 576
5.8.3 Bioactive Ceramics for Tissue Engineering 577
5.8.4 Scaffold Biomaterials for Tissue Engineering 578
5.8.5 Cellular Bioceramics as Scaffolds in Tissue Engineering 580
5.8.5.1 HA and Other Calcium Phosphates 580
5.8.5.2 Melt-Derived Bioactive Glasses 588
5.8.5.3 Sol\u2013Gel-derived Bioactive Glasses 588
5.8.5.4 Other Bioceramics Exhibiting Cellular Structure 592
5.8.6 Properties of Some Selected Bioactive Ceramic Foams 593
5.8.7 Summary 594
5.9 Interpenetrating Composites 599
5.9.1 Introduction 599
5.9.2 Metal\u2013Ceramic Interpenetrating Composites 600
5.9.3 Polymer\u2013Ceramic Interpenetrating Composites 603
5.9.4 Summary 606
5.10 Porous Media in Internal Combustion Engines 608
5.10.1 Introduction 608
5.10.2 Novel Engine Combustion Concepts with Homogeneous Combustion Processes 609
5.10.3 Application of Porous-Medium Technology in IC Engines 611
5.10.4 The PM Engine Concept: Internal Combustion Engine with Mixture Formation and Homogeneous Combustion in a PM Reactor 615
5.10.4.1 PM Engine with Closed PM Chamber 616
5.10.4.2 PM Engine with Open PM Chamber 617
5.10.5 An Update of the MDI Engine Concept: Intelligent Engine Concept with PM Chamber for Mixture Formation 618
5.10.6 Two-Stage Combustion System for DI Diesel Engine 620
5.10.7 Summary 622
5.11 Other Developments and Special Applications 624
5.11.1 Introduction 624
5.11.2 Improving the Mechanical Properties of Reticulated Ceramics 624
5.11.2.1 Ceramic Foams by Reaction Bonding 625
5.11.2.2 Overcoating of Conventional Reticulated Ceramics 626
5.11.2.3 Infiltration of the Struts of Reticulated Ceramics 627
5.11.3 Microcellular Ceramic Foams 628
5.11.4 Porous Ceramics with Aligned Pores 629
5.11.5 Porous Superconducting Ceramics 630
5.11.6 Porous Yb(2)O(3) Ceramic Emitter for Thermophotovoltaic Applications 631
5.11.7 Ceramic Foams for Advanced Thermal Management Applications 632
5.11.8 Ceramic Foams for Impact Applications 634
5.11.8.1 Hypervelocity Impact Shields for Spacecrafts and Satellites 634
5.11.8.2 Armour Systems 636
5.11.9 Heat Exchangers 637
5.11.10 Ceramic Foams for Semiconductor Applications 639
5.11.11 Duplex filters 639
5.11.12 Lightweight Structures 640
5.11.13 Ceramic Foams as Substrates for Carbon Nanotube Growth 641
5.11.14 Metal Oxide Foams as Precursors for Metallic Foams 642
5.11.15 Zeolite Cellular Structures 643
5.11.16 Current Collectors in Solid Oxide Fuel Cells 644
5.11.17 Sound Absorbers 644
5.11.18 Bacteria/Cell Immobilization 645
5.11.19 Light Diffusers 645
5.11.20 Summary 646
Concluding Remarks 649
Index 653