Wear: Materials, Mechanisms and Practice

Tribology is emerging from the realm of steam engines and crank-case lubricants and becoming key to vital new technologies such as nanotechnology and MEMS. Wear is an integral part of tribology, and an effective understanding and appreciation of wear is essential in order to achieve the reliable and efficient operation of almost any machine or device. Knowledge in the field has increased considerably over recent years, and continues to expand: this book is intended to stimulate its readers to contribute towards the progress of this fascinating subject that relates to most of the known disciplines in physical science. Wear – Materials, Mechanisms and Practice provides the reader with a unique insight into our current understanding of wear, based on the contributions of numerous internationally acclaimed specialists in the field. Offers a comprehensive review of current knowledge in the field of wear. Discusses latest topics in wear mechanism classification. Includes coverage of a wide variety of materials such as metals, polymers, polymer composites, diamonds, and diamond-like films and ceramics. Discusses the chemo-mechanical linkages that control tribology, providing a more complete treatment of the subject than just the conventional mechanical treatments. Illustrated throughout with carefully compiled diagrams that provide a unique insight into the controlling mechanisms of tribology. The state of the art research on wear and the mechanisms of wear featured will be of interest to post-graduate students and lecturers in engineering, materials science and chemistry. The practical applications discussed will appeal to practitioners across virtually all sectors of engineering and industry including electronic, mechanical and electrical, quality and reliability and design.

Table of Contents:
List of Contributors xiii Series Editors’ Foreword xvii Preface xix 1 The Challenge of Wear 1 I.M. Hutchings Abstract 1 1.1 Introduction 1 1.2 Definitions and Development of Wear Studies 1 1.3 Scope and Challenges 2 1.4 Conclusions 6 References 6 2 Classification of Wear Mechanisms/Models 9 K. Kato Abstract 9 2.1 Introduction 9 2.2 Classification of Wear Mechanisms and Wear Modes 10 2.2.1 Mechanical, Chemical and Thermal Wear 10 2.2.2 Wear Modes: Abrasive, Adhesive, Flow and Fatigue Wear 11 2.2.3 Corrosive Wear 14 2.2.4 Melt and Diffusive Wear 15 2.3 General Discussion of Wear Mechanisms and Their Models 15 2.3.1 Material Dependence 15 2.3.2 Wear Maps 16 2.3.3 Wear Mode Transition 17 2.3.4 Erosion 17 2.4 Conclusion 18 Acknowledgements 18 References 18 3 Wear of Metals: A Material Approach 21 S.K. Biswas Abstract 21 3.1 Introduction 21 3.2 Mild Wear and Transition to Severe Wear 22 3.2.1 Mild Wear 22 3.2.2 Transition to Severe Wear 23 3.3 Strain Rate Estimates and Bulk Surface Temperature 27 3.3.1 Strain Rate Response Maps 28 3.3.2 Bulk Surface Temperature 30 3.3.3 The Phenomenological Argument 30 3.3.4 Micrographic Observations 31 3.4 Summary 34 3.4.1 Homogeneous Deformation – Severe Wear 34 3.4.2 Homogeneous Deformation – Mild Wear 35 3.4.3 Inhomogeneous Deformation – Severe Wear 35 Acknowledgements 35 References 35 4 Boundary Lubricated Wear 37 S.M. Hsu, R.G. Munro, M.C. Shen, and R.S. Gates Abstract 37 4.1 Introduction 37 4.2 Lubricated Wear Classification 38 4.3 Lubricated Wear Versus “Dry” Wear 38 4.4 Wear Measurement in Well-Lubricated Systems 42 4.5 Measurement Procedures 44 4.5.1 Run-In Process 46 4.5.2 General Performance Wear Test (GPT) 49 4.5.3 Enhanced Oxidation Wear Test (EOT) 52 4.5.4 Boundary Film Persistence Test (BFPT) 53 4.5.5 Case Study with GPT and BFPT 55 4.5.6 Boundary Film Failure Test (BFFT) 57 4.6 Wear Mechanisms Under Lubricated Conditions 61 4.7 Modeling of Lubricated Wear 65 4.7.1 Wear 65 4.7.2 Contact Area 65 4.7.3 Rheology 66 4.7.4 Film Thickness 67 4.7.5 Contact Stress 67 4.7.6 Flash Temperatures 67 4.8 Summary 68 Acknowledgments 69 References 69 5 Wear and Chemistry of Lubricants 71 A. Neville and A. Morina 5.1 Encountering Wear in Tribological Contacts 71 5.2 Lubricant Formulations – Drivers for Change 73 5.3 Tribochemistry and Wear 76 5.4 Antiwear Additive Technologies 77 5.4.1 Antiwear Technologies 77 5.4.2 ZDDP – Antiwear Mechanism 78 5.4.3 Interaction of ZDDP with Other Additives 83 5.4.4 New Antiwear Additive Technologies 87 5.5 Extreme Pressure Additives 88 5.6 Lubricating Non-Fe Materials 89 References 90 6 Surface Chemistry in Tribology 95 A.J. Gellman and N.D. Spencer Abstract 95 6.1 Introduction 95 6.2 Boundary Lubrication and Oiliness Additives 95 6.2.1 Introduction 95 6.2.2 Monolayers, Multilayers and Soaps 96 6.2.3 Viscous Near-Surface Layers 102 6.2.4 Boundary Lubrication in Natural Joints 102 6.2.5 Summary 103 6.3 Zinc Dialkyldithiophosphate 103 6.3.1 Background 103 6.3.2 Analytical Approaches 104 6.3.3 Summary of Film-Formation Mechanism 104 6.3.4 Studies of Film Structure, Composition, and Thickness 105 6.4 Hard Disk Lubrication 109 6.5 Vapor-Phase Lubrication 112 6.6 Tribology of Quasicrystals 115 6.7 Conclusions 118 Acknowledgments 118 References 118 7 Tribology of Engineered Surfaces 123 K. Holmberg and A. Matthews Abstract 123 7.1 Introduction 123 7.2 Definition of an Engineered Surface 125 7.3 Tribomechanisms of Coated Surfaces 125 7.3.1 Scales of Tribology 125 7.3.2 Macromechanical Friction and Wear 126 7.3.3 Micromechanical Mechanisms 131 7.3.4 Modelling Stresses and Strains in a Coated Microcontact 132 7.3.5 Tribochemical Mechanisms 133 7.3.6 Nanoscale Mechanisms 135 7.3.7 Debris Generation and Transfer Layers 136 7.4 Contact Types 139 7.4.1 Sliding 139 7.4.2 Abrasion 141 7.4.3 Impact 141 7.4.4 Surface Fatigue 141 7.4.5 Fretting 142 7.4.6 Chemical Dissolution 143 7.4.7 Lubricated 143 7.5 Advanced Coating Types 144 7.5.1 Hard Binary Compound Coatings 145 7.5.2 Multilayer Coatings 146 7.5.3 Nanocomposite Coatings 149 7.5.4 Hybrid and Duplex Coatings 151 7.6 Applications 152 7.7 Conclusions 154 References 155 8 Wear of Ceramics: Wear Transitions and Tribochemical Reactions 167 S. Jahanmir Abstract 167 8.1 Introduction 168 8.2 Structure and Properties of Ceramics 168 8.2.1 Alumina Ceramics 168 8.2.2 Silicon Nitride Ceramics 169 8.2.3 Silicon Carbide Ceramics 170 8.3 Wear Transitions 170 8.3.1 Alumina 171 8.3.2 Silicon Nitride 174 8.3.3 Silicon Carbide 175 8.4 Damage Formation in Hertzian Contacts 177 8.4.1 Brittle Behavior 177 8.4.2 Quasi-Plastic Behavior 177 8.4.3 Brittleness Index 180 8.5 Transition Loads in Sliding Contacts 181 8.5.1 Quasi-Plastic Behavior 181 8.5.2 Brittle Behavior 183 8.5.3 Transition from Brittle Fracture to Quasi-Plasticity 184 8.6 Ceramics in Tribological Applications 185 Acknowledgments 187 References 187 9 Tribology of Diamond and Diamond-Like Carbon Films: An Overview 191 A. Erdemir and Ch. Donnet Abstract 191 9.1 General Overview 192 9.2 Diamond Films 194 9.2.1 Deposition and Film Microstructure 194 9.2.2 Tribology of Diamond Films 195 9.2.3 Practical Applications 204 9.3 Diamond-like Carbon Films 207 9.3.1 Structure and Composition 207 9.3.2 Tribology of DLC Films 209 9.3.3 Synthesis of Carbon Films with Superlow-Friction and -Wear Properties 215 9.3.4 Practical Applications 217 9.4 Summary and Future Direction 219 Acknowledgments 219 References 220 10 Tribology of Polymeric Solids and Their Composites 223 B.J. Briscoe and S.K. Sinha Abstract 223 10.1 Introduction 224 10.2 The Mechanisms of Polymer Friction 225 10.2.1 The Ploughing Term – Brief Summary 225 10.2.2 The Adhesion Term – Brief Summary 227 10.3 Wear 228 10.3.1 Semantics and Rationalizations 228 10.3.2 Wear Classification Based on Generic Scaling Responses 230 10.3.3 Phenomenological Classification of Wear Damages 232 10.3.4 Wear Classification Based on Polymeric Responses 240 10.4 Tribology of Polymer Composites 249 10.4.1 ‘Soft and Lubricating’ Phases in a Harder Matrix 249 10.4.2 ‘Hard and Strong’ Phases in a ‘Soft’ Matrix 250 10.4.3 Hybrid Polymer Composites 253 10.5 Environmental and Lubrication Effects 254 10.6 A Case Study: Polymers in Hip and Knee Prosthetic Applications – Ultrahigh-Molecular-Weight Poly(ethylene) (UHMWPE) 256 10.7 Concluding Remarks 260 Acknowledgements 261 References 261 11 Wear of Polymer Composites 269 K. Friedrich, Z. Zhang and P. Klein Abstract 269 11.1 Introduction 269 11.2 Sliding Wear of Filler Reinforced Polymer Composites 270 11.2.1 Short Fibres and Internal Lubricants 270 11.2.2 PTFE Matrix Composites 272 11.2.3 Micro- and Nanoparticle Reinforcements 275 11.2.4 Integration of Traditional Fillers with Inorganic Nanoparticles 277 11.2.5 Functionally Graded Tribo-Materials 279 11.3 Artificial Neural Networks Approach for Wear Prediction 280 11.4 Fibre Orientation, Wear Mechanisms and Stress Conditions in Continuous Fibre Reinforced Composites 282 11.5 Conclusions 286 Acknowledgements 286 References 287 12 Third-Body Reality – Consequences and Use of the Third-Body Concept to Solve Friction and Wear Problems 291 Y. Berthier Abstract 291 12.1 Introduction 292 12.2 Relationship Between the Third Body and Friction 292 12.2.1 Boundary Conditions 292 12.2.2 Friction Analysis 292 12.3 Relationship Between the Third Body and Wear 293 12.3.1 Wear Laws 293 12.3.2 Material Hardness and Wear 294 12.4 What Methods Exist for Studying Friction and Wear? 294 12.4.1 The Scientific Context Surrounding Tribology 294 12.4.2 Physical Difficulties Related to Studying Contacts 295 12.4.3 So Where to from Here? 297 12.5 The Third-Body Concept 298 12.5.1 Artificial and Natural Third Bodies 298 12.5.2 Contact Without the Third Body 299 12.5.3 Types of “Solid” Third Body from the Mechanical Viewpoint 299 12.5.4 “Action Heights” of Third Bodies 300 12.6 Functions and Behaviour of the Third Body 300 12.6.1 Functions of the Third Body 300 12.6.2 Operation of Solid Third Bodies 301 12.6.3 Tribological Circuit of Third-Body Flows 302 12.6.4 Rheology of the Third Body 303 12.6.5 Scientific and Technological Consequences of the Tribological Circuit 303 12.7 Roles of the Materials in a Tribological Contact 304 12.7.1 Indirect Role of the Materials – Scale of the Actual Mechanism or Mechanical Device 304 12.7.2 Direct Role of the Materials – Scale of First Bodies 304 12.7.3 Optimal Direct Response of Material to the Tribological Contact 305 12.7.4 Consequences on the Approach Used for Solving Technological Problems 306 12.8 Taking into Account the Effects of the Mechanism 306 12.8.1 Choosing the Conditions to be Modelled 306 12.8.2 Technological Consequences of the Effects of the Mechanism 307 12.9 Taking into Account the Effect of the First Bodies 307 12.9.1 Local Contact Dynamics 307 12.9.2 Technological Consequences of the Effects of the First Bodies 307 12.10 “Solid” Natural Third-Body Modelling 308 12.10.1 Reconstruction of the Tribological Circuit 308 12.10.2 Technological Consequences of the Third Body 309 12.11 Correspondence of the Strategy Proposed to Reality 310 12.12 Control of Input Conditions 310 12.12.1 Objectives 310 12.12.2 Procedure 311 12.12.3 Precautions 311 12.13 Performing Experiments 312 12.13.1 Initial Conditions 312 12.13.2 Exterior of the Contact 313 12.13.3 Interior of the Contact 313 12.14 Conclusions 314 Acknowledgements 314 References 315 13 Basic Principles of Fretting 317 P. Kapsa, S. Fouvry and L. Vincent Abstract 317 13.1 Introduction 317 13.2 Wear 319 13.3 Industrial Needs 320 13.4 Fretting in Assemblies 321 13.5 Fretting Processes 322 13.6 Fretting Parameters 330 13.6.1 Nature of Loading 330 13.6.2 Nature of the First Bodies 331 13.6.3 Coatings 332 13.6.4 Environment 334 13.6.5 Frequency 335 13.6.6 Temperature 335 13.7 Conclusions 336 References 337 14 Characterization and Classification of Abrasive Particles and Surfaces 339 G.W. Stachowiak, G.B. Stachowiak, D. De Pellegrin and P. Podsiadlo Abstract 339 14.1 Introduction 340 14.2 General Descriptors of Particle Shape 340 14.3 Particle Angularity Parameters 341 14.3.1 Angularity Parameters SP and SPQ and Their Relation to Abrasive and Erosive Wear 342 14.3.2 Cone-Fit Analysis (CFA) 344 14.3.3 Sharpness Analysis 349 14.4 Particle Size Effect in Abrasive Wear 353 14.5 Sharpness of Surfaces 356 14.5.1 Characterization of Surface Sharpness by the Modified SPQ Method 356 14.5.2 Characterization of Surface Sharpness by SA 358 14.6 Classification of Abrasive Surfaces 359 14.7 Summary 364 Acknowledgements 365 References 365 15 Wear Mapping of Materials 369 S.M. Hsu and M.C. Shen 15.1 Introduction 369 15.1.1 Wear – A System Perspective 370 15.1.2 Historical Material Selection Guide 370 15.2 Basic Definition of Wear 372 15.2.1 Nature of Wear 372 15.2.2 Wear Characterization 372 15.3 Wear as a System Function 375 15.4 Wear Maps as a Classification Tool to Define the System 376 15.5 Wear as an “Intrinsic” Material Property as Defined by Wear Maps 377 15.6 Different Kinds of Wear Maps 378 15.7 Application of Wear Maps 380 15.7.1 Material Comparison Based on Wear Maps 381 15.7.2 Wear Transition Diagrams 385 15.7.3 Material Selection Guided by Wear Maps 389 15.7.4 Wear Mechanism Identification 391 15.7.5 Wear Modeling Guide Based on Wear Maps 396 15.7.6 Wear Prediction Based on Wear Maps 405 15.8 Construction Techniques of Wear Maps 411 15.8.1 Conducting Wear Experiments 411 15.8.2 Wear Data 412 15.8.3 Data Trend Analysis 413 15.8.4 Wear Mapping 414 15.8.5 Selection of Parameters for Mapping 416 15.8.6 Assumptions in the Step-Loading Test Procedure 418 15.9 Application Map Concept and Examples 420 15.10 Future Wear Map Research 421 References 422 16 Machine Failure and Its Avoidance – Tribology’s Contribution to Effective Maintenance of Critical Machinery 425 B.J. Roylance Abstract 425 16.1 Introduction 425 16.2 Maintenance Practice and Tribological Principles 426 16.2.1 Maintenance Practice – A Brief Historical Overview 426 16.2.2 Tribological Principles 427 16.2.3 Tribology and Maintenance 431 16.3 Failure Diagnoses 432 16.3.1 Failure Morphology and Analysis 432 16.3.2 Dealing with Failure – Two Short Case Studies 434 16.3.3 Comment 436 16.4 Condition-Based Maintenance 436 16.5 Wear and Wear Debris Analysis 440 16.5.1 Wear Modes and Associated Debris Characteristics – Some Experimental Results and Their Application to RAF Early Failure Detection Centres 443 16.5.2 Summary of Laboratory Test Results 445 16.5.3 Wear Particle Classification and Application 446 16.6 Predicting the Remaining Useful Life and Evaluating the Cost Benefits 448 16.6.1 Remaining Useful Life Predictions 448 16.6.2 Evaluating the Cost Benefits 449 16.7 Closure 450 Acknowledgements 450 References 451 Index 453