Wear: Materials, Mechanisms and Practice

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