High Temperature Corrosion Fundamentals and Engineering

Preface xi Acknowledgments xvii 1 Introduction 1 1.1 Definition of High Temperature Corrosion 1 1.2 Historical Development 1 1.3 High Temperature Corrosion Phenomena 3 1.4 High Temperature Materials 3 1.5 Corrosive Environments 27 1.6 Films and Scales 31 1.7 Academic Impact of High Temperature Corrosion 33 1.8 Industrial Impact of High Temperature Corrosion 38 1.9 Questions 46 References 46 Further Reading 47 2 Metallurgical Structure and Metals 48 2.1 Imperfections in an Essentially Perfect Structure 48 2.2 Solidification 56 2.3 Alloys 62 2.4 Iron and Steel 72 2.5 Deformation and Recrystallization 79 2.6 Fracture and Fatigue 91 2.7 Questions and Problems 97 References 98 Further Reading 99 3 High Temperature Equilibria 100 3.1 Introduction 100 3.2 Thermochemical Analysis 100 3.3 Electrochemical Analysis 119 References 128 Further Reading 129 4 Lattice Defects in Metal Compounds 130 4.1 Introduction 130 4.2 Defect Reactions 133 4.3 Defect Equilibria 135 4.4 Equilibrium Constants 141 4.5 Questions 144 References 144 Further Reading 145 5 Diffusion in Solid-State Systems 146 5.1 Introduction 146 5.2 General Theory of Diffusion 146 5.3 Diffusion Coefficients 150 5.4 Matano-Boltzmann Analysis 153 5.5 Kirkendall Effect 154 5.6 Darken Analysis 155 5.7 Factors Influencing Diffusion 156 5.8 Impurity Diffusion in Metals 158 5.9 Grain Boundary Diffusion in Metals 158 5.10 Diffusion in Solid Oxides 160 5.11 Morphology of Reaction Products 163 5.12 Measurement of Diffusion Parameters 164 5.13 Questions and Problems 168 References 168 Further Reading 169 6 High Temperature Electrochemistry 171 6.1 Introduction 171 6.2 Electrochemical Nature of Molten Salt Corrosion 171 6.3 The Single Potential of an Electrode 172 6.4 Equilibrium Diagrams 173 6.5 The Tafel Relationship 173 6.6 Corrosion Potential-pO2 Relationship 175 6.7 Electrochemical Polarization and Monitoring 177 6.8 Electrochemical Nature of Metal Oxidation 179 6.9 Usefulness of Electrochemical Cells 181 6.10 Current-Potential Measurements on Solid Electrodes 182 6.11 Simple Concepts of Oxide Semiconductors 183 6.12 Conduction Processes in Ionic Oxides 186 6.13 Common Solid-State Electrochemical Situations 190 References 194 Further Reading 195 7 Oxidation 196 7.1 Introduction 196 7.2 Thermodynamic Considerations 197 7.3 Kinetic Considerations 199 7.4 Defect Structures 201 7.5 Compact Scale Growth 208 7.6 Multilayered Scale Growth 212 7.7 Oxidation Resistance 214 7.8 Oxidation of Engineering Materials 224 7.9 Conclusions 228 7.10 Questions 229 References 229 Further Reading 231 8 Sulfidation 233 8.1 Introduction 233 8.2 The Process of Sulfidation 233 8.3 Sulfidation Kinetics 235 8.4 Sulfidation of Selected Materials 236 8.5 Defect Structures of Metal Sulfides 240 8.6 Questions 243 References 243 Further Reading 244 9 Carburization and Metal Dusting 245 9.1 Introduction 245 9.2 Carburization 245 9.3 Alloy Resistance to Carburization 251 9.4 Metal Dusting Problem 255 9.5 Metal Dusting Mechanisms 256 9.6 Alloy Resistance to Metal Dusting 260 References 262 Further Reading 263 10 Nitridation 264 10.1 Introduction 264 10.2 Nitridation Mechanisms 264 10.3 Nitridation in Industrial Media 265 10.4 Questions and Problems 273 References 274 Further Reading 275 11 Halogenation 276 11.1 Introduction 276 11.2 Metal-Halogen Reactions 277 11.3 Alloy-Halogen Reactions 279 11.4 Laboratory Studies 280 11.5 Conclusions 282 11.6 Questions 282 References 282 Further Reading 283 12 Corrosion by Hydrogen and Water Vapor 284 12.1 Introduction 284 12.2 Corrosion by Hydrogen 284 12.3 Corrosion by Water Vapor 290 12.4 Conclusions 293 References 294 Further Reading 295 13 Corrosion in Molten Salts 296 13.1 Introduction 296 13.2 Corrosion Process 296 13.3 Thermodynamic Diagrams 298 13.4 Corrosion Rate Measurements 299 13.5 Test Methods 299 13.6 Fluorides 303 13.7 Chlorides 304 13.8 Nitrates/nitrites 305 13.9 Hydroxides 309 13.10 Carbonates 309 13.11 Vanadates 312 13.12 Sulfates 314 13.13 Prevention of Molten Salt Corrosion 321 13.14 Summary 321 References 322 Further Reading 324 14 Corrosion in Molten Metals 325 14.1 Introduction 325 14.2 Corrosive Processes 326 14.3 Industrial Liquid Metals 332 14.4 Conclusions 338 References 339 Further Reading 339 15 Hot Corrosion 340 15.1 Introduction 340 15.2 Engine Description and Materials 340 15.3 Early Studies 341 15.4 Mechanisms of Hot Corrosion 349 15.5 Hot Corrosion of Gas Turbine Alloys 351 15.6 Methods of Evaluating Hot Corrosion 354 15.7 Prevention of Corrosion 356 15.8 Conclusions 358 15.9 Questions 358 References 359 Further Reading 360 16 Fireside Corrosion 361 16.1 Introduction 361 16.2 Coal-Fired Boilers 362 16.3 Coal-ash Corrosion 371 16.4 Oil-Fired Boilers 373 16.5 Corrosion in Waste Incinerators 379 16.6 Plant Experience with Fireside Corrosion 380 16.7 Conclusions 388 References 389 Further Reading 389 17 Testing and Evaluation 391 17.1 Introduction 391 17.2 Testing Equipment and Monitoring 392 17.3 Optical Microscopy 394 17.4 Thermogravimetry 395 17.5 Spectroscopy 398 17.6 Diffraction Techniques 402 17.7 Electron Microscopy 409 17.8 Electron Spectroscopy and Ion Scattering 416 17.9 Surface Microscopy 424 17.10 Optical Spectroscopy 428 17.11 Nondestructive Inspection Techniques 439 17.12 Traditional Electrochemical Methods 445 17.13 Nontraditional Electrochemical Methods 453 17.14 Combined Electrochemical Methods 459 References 472 Further Reading 475 18 Protective Coatings 477 18.1 Introduction 477 18.2 Coating Systems 477 18.3 Coating Processes 480 18.4 Coating Degradation 496 18.5 Summary and Future Trends 499 18.6 Questions 500 References 500 Further Reading 501 19 Examples of Engineering Importance 502 19.1 Introduction 502 19.2 Molten Carbonate Fuel Cells 504 19.3 Solid Oxide Fuel Cells 516 19.4 Direct Carbon Fuel Cells 524 19.5 Nuclear Power Plants 531 References 546 Further Reading 549 20 Case Studies 551 20.1 Making Stainless Steels 551 20.2 Corrosion Protection of Turbine Blades 551 20.3 Oxidation of Silicides for VLSI Applications 556 20.4 Naphthenic Acid Corrosion in Petrochemical Plants 560 20.5 Oxidation of Ceramic Matrix Composites 562 20.6 Shell Corrosion of Rotary Cement Kilns 563 20.7 Corrosion of Steels in a Linear ?Olefin Plant 564 References 565 Further Reading 565 Appendix A 566 List of Acronyms 591 Glossary of Selected Terms Used in High Temperature Corrosion 596 Author Index 615 Subject Index 629