1．General Introduction to Porous Materials 1
1.1 Elementary Concepts for Porous Materials 1
1.2 Main Groups of Porous Materials 2
1.3 Porous Metals 6
1.3.1 Powder-sintering type 6
1.3.2 Fiber-sintering type 8
1.3.3 Melt-casting type 8
1.3.4 Metal-deposition type 9
1.3.5 Directional-solidification type 10
1.3.6 Composite type 10
1.4 Porous Ceramics 11
1.4.1 Classifying porous ceramics 12
1.4.2 Characteristics of porous ceramics 14
1.5 Polymer Foams 15
1.5.1 Classifying polymer foams 15
1.5.2 Characteristics of polymer foams 17
1.6 Conclusions 19
References 19
2．Making Porous Metals 21
2.1 Powder Metallurgy 21
2.1.1 Preparation of metal powders 22
2.1.2 Molding of the porous body 28
2.1.3 Sintering of the porous body 34
2.2 Fiber Sintering 50
2.2.1 Preparation of metal fibers 51
2.2.2 Preparation of porous bodies 53
2.2.3 Electrode plate with porous metal fibers 55
2.3 Metallic Melt Foaming 57
2.3.1 Preparation of porous bodies 57
2.3.2 Technical problems and solutions 58
2.3.3 Case studies on porous aluminum preparation 60
2.4 Gas Injection into the Metallic Melt 61
2.5 Infiltration Casting 65
2.6 Metal Deposition 69
2.6.1 Vapor deposition 69
2.6.2 Electrodeposition 73
2.6.3 Reaction deposition 83
2.7 Hollow Ball Sintering 83
2.7.1 Preparation of hollow balls 84
2.7.2 Preparation of porous bodies 85
2.7.3 Fe-Cr alloy porous products 86
2.8 Preparation of the Directional Porous Metal 86
2.8.1 Solid-gas eutectic solidification 86
2.8.2 Directional solidification 89
2.9 Other Methods 92
2.9.1 Powder melting foaming 92
2.9.2 Investment casting 95
2.9.3 Self-propagating,high-temperature synthesis(SHS) 96
2.10 Preparation of Porous Metal Composites 99
2.11 Special Processing of Porous Metals 104
2.12 Concluding Remarks 107
References 108
3．Application of Porous Metals 113
3.1 Introduction 113
3.1.1 Functional applications 113
3.1.2 Structural applications 114
3.2 Filtation and Separation 115
3.2.1 Industrial filtration 116
3.2.2 Gas purification 116
3.3 Sound Absorption 120
3.3.1 Sound absorption mechanism of metal foams 121
3.3.2 Influence factor of sound absorption 123
3.3.3 Metal foam with improved sound absorption 126
3.3.4 Applications 128
3.3.5 The model for calculation of sound absorption coefficient 130
3.4 Heat Exchange 133
3.4.1 Heat exchanger 134
3.4.2 Heat radiator 135
3.4.3 Heat tube 136
3.4.4 Resistance heater 137
3.4.5 Composite phase transformation materials 139
3.4.6 Cooling materials 141
3.5 Porous Electrode 141
3.5.1 Nickel foam 143
3.5.2 Pb foam 143
3.5.3 Fuel cell 145
3.6 Application in Transportation 146
3.6.1 Light structure 147
3.6.2 Absorption of impact energy 148
3.6.3 Noise control 148
3.6.4 Other options 149
3.7 Applications in Biology and latrology 151
3.7.1 Applicability of materials 151
3.7.2 Mechanical requirements 153
3.7.3 Ti foam 154
3.7.4 Ta and stainless steel foams 157
3.7.5 Gradient structure and composite 159
3.7.6 Mechanism of bone formation 160
3.8 Other Applications 162
3.8.1 Energy absorption and vibration control 162
3.8.2 Electromagnetic shielding 166
3.8.3 Fighting flames 167
3.8.4 Mechanical parts 168
3.8.5 Building materials 171
3.8.6 Catalytic reactions 172
3.9 Some Application Illustrations for Refractory Metal Porous Products 176
3.9.1 W foam 176
3.9.2 Ta foam 178
3.9.3 Mo foam 179
3.10 Concluding Remarks 181
References 182
4．Special Porous Metals 189
4.1 Amorphous Metal Foams(AMFs) 189
4.2 Gradient Porous Metals 193
4.3 Porous Metallic Lattice Materials 198
4.4 Nanoporous Metal Foams(NMFs) 203
4.5 Porous Metallic Films and Thin Films Carried on Metal Foams 215
4.5.1 Porous metallic films 215
4.5.2 Thin films carried on metal foam 216
4.6 Conclusions 218
References 219
5．Fabricating Porous Ceramics 221
5.1 Particle Stacking Sintering 222
5.2 Appending Pore-forming Agent 223
5.2.1 Addition of pore-forming material in powders 223
5.2.2 Slurry with pore-forming agent 228
5.3 Polymeric Sponge Impregnation Process 233
5.3.1 The selection of organic foam and the pretreatment 234
5.3.2 Ceramic slurry preparation and impregnating 234
5.3.3 Drying and sintering of green bodies 238
5.3.4 Progress of organic foam impregnating in slurry 239
5.3.5 The obtainment of the ceramic foam with high strength 241
5.4 Foaming Process 244
5.4.1 Green body foaming 244
5.4.2 Slurry foaming 246
5.4.3 Evaluation of the processing 253
5.5 Sol-gel Method 255
5.5.1 Different templates 255
5.5.2 Example of preparation of porous ceramics 256
5.6 New Processing of Porous Ceramics 258
5.6.1 Gel casting 258
5.6.2 Wood ceramics 262
5.6.3 Freeze-drying method 264
5.6.4 Self-propagating high-temperature synthesis(SHS) 265
5.6.5 Hollow-sphere sintering 266
5.6.6 Other processes 268
5.7 The Preparation of New Types of Porous Ceramic 270
5.7.1 Hydrophobic porous ceramics 270
5.7.2 Ceramic foam with gradient pores 271
5.7.3 Fiber-porous ceramics 274
5.7.4 Slender porous ceramic tubes 275
5.7.5 Porous ceramics with directionally arrayed pores 277
5.7.6 Porous ceramic powder 277
5.8 Preparation of Porous Ceramic Membranes 278
5.8.1 Sol-gel 279
5.8.2 Other methods 280
5.8.3 Preparation examples for porous ceramic membranes 281
5.8.4 A porous TiO2 film with submicropores 283
5.9 Porous Ceramic Composites 292
5.10 Ceramic Honeycombs 295
5.11 Concluding Remarks 296
References 296
6．Applications of Porous Ceramics 303
6.1 Filtration and Separation 303
6.1.1 Filtration of molten metals 304
6.1.2 Hot gas filtration 310
6.1.3 Microfiltration 311
6.1.4 Fluid separation 312
6.1.5 Parameters of separation and filtration 315
6.2 Functional Materials 316
6.2.1 Biological materials 316
6.2.2 Ecomaterials(Environmental materials) 319
6.2.3 Heat insulation and exchange 321
6.2.4 Sound absorption and damping 322
6.2.5 Sensors(sensing elements) 330
6.3 Chemical Engineering 331
6.3.1 Catalyst carriers 331
6.3.2 Porous electrodes and membranes 333
6.3.3 Ion exchange and desiccants 337
6.3.4 Gas introduction 337
6.4 Combustion and Fire Retardance 338
6.4.1 Combustor 338
6.4.2 Flame arrester 339
6.5 Overall Comments on the Application of Porous Ceramics 339
6.6 Concluding Remarks 341
References 342
7．Producing Polymer Foams 345
7.1 The Foaming Mechanism of Plastic Foam 345
7.1.1 Raw materials 345
7.1.2 Foaming methods 352
7.1.3 Formation of bubble nuclei 354
7.1.4 Growth of bubbles 355
7.1.5 Stabilization and solidification of the foamed body 357
7.1.6 The foaming of some plastics 360
7.2 Molding Process for Polymer Foams 361
7.2.1 Extrusion foaming 361
7.2.2 Injection molding 362
7.2.3 Pour foaming 363
7.2.4 Mold pressing 364
7.2.5 Reaction injection molding(RIM) 364
7.2.6 Rotation foaming 366
7.2.7 Hollow blowing 366
7.2.8 Microwave sintering 367
7.3 Flame-Retardant Polymer Foam 367
7.3.1 Anti-flaming 368
7.3.2 Common flame-retarding plastic foams 369
7.4 Progress of Plastic Foam Preparation 371
7.4.1 Modification of traditional foamed plastics 372
7.4.2 Microcellular plastics 373
7.4.3 Sound-absorbing plastic foams 374
7.4.4 Biodegradable foamed plastics 374
7.4.5 Reinforced foamed plastic 375
7.4.6 Posttreatment of foamed plastics 375
7.4.7 Plant oil-based plastic foams 376
7.4.8 PU plastic foam 377
7.5 Concluding Remarks 378
References 379
8．Applications of Polymer Foams 383
8.1 Thermal Insulation Materials 383
8.1.1 Factors affecting thermal insulation performance 384
8.1.2 Thermal insulation and energy saving construction 384
8.2 Packaging Materials 385
8.3 Sound-Absorbing Materials 387
8.3.1 Product features 387
8.3.2 Sound absorption principles and mechanisms 388
8.3.3 PU foam 389
8.4 Separation and Enrichment 389
8.4.1 Working principles 390
8.4.2 Modification application 391
8.4.3 Enrichment of organic poisonous matters 393
8.5 Other Applications 393
8.5.1 Dust arrestment 393
8.5.2 Structural materials 394
8.5.3 Fireproofing technology and active explosion suppression 395
8.5.4 Buoyancy 396
8.6 Applications of Typical Kinds of Polymer Foam 396
8.6.1 Thermosetting polymer foams 397
8.6.2 Thermoplastic general polymer foams 399
8.6.3 Engineering thermoplastic foams 401
8.6.4 High-temperature-resistant polymer foams(using temperatures higher than 200℃) 402
8.6.5 Functional polymer foams 402
8.6.6 Other polymer foams 403
8.7 New,Functional Polymer Foams 404
8.7.1 Microcellular plastics 404
8.7.2 Magnetic polymer foams 405
8.7.3 Porous,self-lubricating plastics 406
8.8 Overall Application Review of Polymer Foams 407
8.9 Conclusions 407
References 408
9．Characterization Methods:Basic Factors 411
9.1 Porosity 411
9.1.1 Basic mathematical relationship 412
9.1.2 Microscopic analysis 412
9.1.3 Mass-volume direct calculation 413
9.1.4 Soaking medium 414
9.1.5 Vacuum dipping 416
9.1.6 Floating 417
9.2 Pore Size 419
9.2.1 Microscopic analysis 420
9.2.2 Bubble method 420
9.2.3 Penetrant method 432
9.2.4 Gas permeation 433
9.2.5 Liquid-liquid method 437
9.2.6 Gas adsorption 442
9.3 Pore Morphology 447
9.3.1 Microobservation method 447
9.3.2 X-Ray tomography 448
9.3.3 Potential examination by DC of pore defects 460
9.3.4 Other methods 463
9.4 Specific Surface Area 464
9.4.1 Gas adsorption method(BET method) 464
9.4.2 Fluid penetrant method 473
9.5 Mercury Intrusion Method 475
9.5.1 Principle of mercury intrusion 476
9.5.2 Measurement of pore size and distribution 477
9.5.3 Measurement of specific surface area 479
9.5.4 Measurement of apparent density and porosity 480
9.5.5 Experimental instrument for mercury intrusion 483
9.5.6 Measurement error analysis and treatment 483
9.5.7 Scope of application 487
9.5.8 Comparison of the different methods 488
9.6 Concluding Remarks 489
References 490
10．Characterization Methods:Physical Properties 493
10.1 Sound Absorption Coefficient 493
10.1.1 Characterization of sound absorbability 494
10.1.2 Measurement of the sound absorption coefficient 495
10.1.3 Analysis and discussion 505
10.2 Thermal Conductivity 507
10.2.1 Characterization of thermal conductivity and diffusivity 507
10.2.2 Measurement of thermal conductivity 509
10.2.3 Measurement of thermal conductivity for porous materials 514
10.2.4 Evaluation of performance 521
10.3 Electrical resistivity/Electrical Conductivity 523
10.3.1 Four-probe method 523
10.3.2 Double bridge method 524
10.3.3 Potentiometer method 528
10.3.4 Eddy method 529
10.4 Concluding Remarks 531
References 532
Index 533