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COATINGS TRIBOLOGY

TRIBOLOGY AND INTERFACE ENGINEERING SERIESEditorBrian Briscoe (UK)Advisory BoardM.J. Adams (U.K.)J.H. Beynon (U.K.)D.V. Boger (Australia)P. Cann (U.K.)K. Friedrich (Germany)I.M. Hutchings (U.K.)Vol. 27Vol. Vol. 37Vol. 38Vol. Vol.Vol.Vol.404142434445464748495052535455J. Israelachvili (U.S.A.)S. Jahanmir (U.S.A.)A.A. Lubrecht (France)I.L. Singer (U.S.A.)G.W. Stachowiak (Australia)Dissipative Processes in Tribology (Dowson et al., Editors)Coatings Tribology – Properties, Techniques and Applications in SurfaceEngineering (Holmberg and Matthews)Friction Surface Phenomena (Shpenkov)Lubricants and Lubrication (Dowson et al., Editors)The Third Body Concept: Interpretation of Tribological Phenomena (Dowson et al., Editors)Elastohydrodynamics – ’96: Fundamentals and Applications in Lubricationand Traction (Dowson et al., Editors)Hydrodynamic Lubrication – Bearings and Thrust Bearings (Frêne et al.)Tribology for Energy Conservation (Dowson et al., Editors)Molybdenum Disulphide Lubrication (Lansdown)Lubrication at the Frontier – The Role of the Interface and Surface Layersin the Thin Film and Boundary Regime (Dowson et al., Editors)Multilevel Methods in Lubrication (Venner and Lubrecht)Thinning Films and Tribological Interfaces (Dowson et al., Editors)Tribological Research: From Model Experiment to Industrial Problem(Dalmaz et al., Editors)Boundary and Mixed Lubrication: Science and Applications (Dowson et al., Editors)Tribological Research and Design for Engineering Systems (Dowson et al., Editors)Lubricated Wear – Science and Technology (Sethuramiah)Transient Processes in Tribology (Lubrecht, Editor)Experimental Methods in Tribology (Stachowiak and Batchelor)Tribochemistry of Lubricating Oils (Pawlak)An Intelligent System For Tribological Design In Engines (Zhang and Gui)Tribology of Elastomers (Si-Wei Zhang)Life Cycle Tribology (Dowson et al., Editors)Tribology in Electrical Environments (Briscoe, Editor)Tribology & Biophysics of Artificial Joints (Pinchuk)Tribology of Metal Cutting (Astakhov)Acoustic Emission in Friction (Baranov et al.)High Pressure Rheology for Quantitative Elastohydrodynamics (Bair)Tribology of Polymeric Nanocomposites: Friction and Wear of Bulk Materials and Coatings(Friedrich and Schlarb)Aims & ScopeThe Tribology Book Series is well established as a major and seminal archival source for definitive bookson the subject of classical tribology. The scope of the Series has been widened to include other facets ofthe now-recognised and expanding topic of Interface Engineering.The expanded content will now include: colloid and multiphase systems; rheology; colloids; tribology and erosion; processing systems; machining; interfaces and adhesion; as well as the classical tribology content which will continue toinclude friction; contact damage; lubrication; and wear at all length scales.

TRIBOLOGY AND INTERFACE ENGINEERING SERIES, 56EDITOR: B.J. BRISCOECOATINGS TRIBOLOGYProperties, Mechanisms, Techniquesand Applications in SurfaceEngineeringSecond EditionKenneth HolmbergVTT – Technical Research Centre of FinlandAllan MatthewsThe University of Sheffield, UKAmsterdam Boston Heidelberg London New York OxfordParis San Diego San Francisco Singapore Sydney Tokyo

ElsevierRadarweg 29, PO Box 211, 1000 AE Amsterdam, The NetherlandsThe Boulevard, Langford Lane, Kidlington, Oxford OX5 IGB, UKFirst edition 1994Copyright Ó 2009 Elsevier B.V. All rights reservedNo part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any meanselectronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisherPermissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone( 44) (0) 1865 843830; fax( 44) (0) 1865 853333; email: permissions@elsevier.com. Alternatively you can submit yourrequest online by visiting the Elsevier web site at http://elsevier.com/locate/permissions, and selecting obtainingpermission to use Elsevier materialNoticeNo responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of productsliability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas containedin the material herein. Because of rapid advances in the medical sciences, in particular, independent verification ofdiagnoses and drug dosages should be madeBritish Library Cataloguing in Publication DataHolmberg, Kenneth.Coatings tribology: contact mechanisms, depositiontechniques and application. – 2nd ed. – (Tribology andinterface engineering series; v. 56)1. Tribology. 2. Coatings.I. Title II. Series III. Matthews, A. (Allan)621.80 9-dc22Library of Congress Cataloging-in-Publication DataA catalog record for this book is available from the Library of CongressLibrary of Congress Control Number: 2009920710ISBN: 978-0-444-52750-9ISSN: 1572-3364For information on all Elsevier publicationsvisit our web site at books.elsevier.comPrinted and bound in Great Britain09 10 11 12 13 10 9 8 7 6 5 4 3 2 1

ToVille, Maya and HannaandDave and Lynda

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CONTENTSPREFACExiACKNOWLEDGEMENTSxiiNOTATIONxiii1 Introduction12 Deposition processes and coating structures2.1 Introduction2.2 Gaseous state processes2.2.1 General2.2.2 Chemical vapour deposition2.2.3 Physical vapour deposition2.2.4 Ion and laser beam-assisted deposition and surface treatment2.3 Solution state processes2.3.1 Chemical solution deposition2.3.2 Electrochemical deposition2.3.3 Sol-gel processing2.3.4 Plasma electrolysis2.4 Molten and semi-molten state processes2.4.1 Laser surface treatments2.4.2 Thermal spraying2.4.3 Welding2.4.4 Other developments2.5 Surface hardening treatments2.6 Process effects on coating structures2.6.1 Morphological growth structures2.6.2 Composite structures7788912212324252627272828282930313133vii

viiiContents3 Tribology of coatings3.1 Friction, wear and lubrication3.1.1 General3.1.2 Surface characteristics3.1.3 Friction3.1.4 Wear3.1.5 Lubrication3.2 Surface stresses and response to loading3.2.1 Response of materials to loading3.2.2 Material parameters E, sy , H, G and Kc3.2.3 Analytical solutions of contact stresses and deformations at surfacesof solid materials3.2.4 Criteria for plastic yield3.2.5 Criteria for material fracture3.2.6 Analytical solutions of stresses and deformations in normallyloaded coated surfaces3.2.7 Analytical solutions of stresses and deformations in normally andtangentially loaded coated surfaces3.2.8 Finite element method modelling and simulation of stresses and deformations3.2.9 Influence of surface roughness3.2.10 Residual stresses3.2.11 Influence of interface cracks3.3 Surface fracture and wear products3.3.1 Crack nucleation3.3.2 Surface crack propagation3.3.3 Crack growth in coated surfaces3.3.4 Toughness and fracture toughness in coated surfaces3.3.5 Crack patterns3.3.6 Coating to substrate adhesion3.3.7 Debris generation and particle agglomeration3.3.8 Transfer layers3.3.9 Tribochemical reaction layers3.4 Tribological mechanisms in coated surfaces3.4.1 Scales in tribology3.4.2 Macromechanical friction mechanisms3.4.3 Macromechanical wear mechanisms3.4.4 Micromechanical tribological mechanisms3.4.5 Tribochemical mechanisms3.4.6 Nanophysical tribological mechanisms3.4.7 Lubricated coated contacts4 Tribological properties of coatings4.1 General4.2 Soft coatings4.2.1 Polymer coatings4.2.2 Soft metal coatings4.3 Lamellar coatings4.3.1 Properties of molybdenum disulphide4.3.2 Burnished and bonded molybdenum disulphide coatings4.3.3 PVD deposited molybdenum disulphide 175185185186186197211211212214

Contents4.4 Hard coatings4.4.1 Titanium nitride coatings4.4.2 Other nitride coatings4.4.3 Carbide coatings4.4.4 Oxide coatings4.4.5 Boride coatings4.5 Carbon and carbon-based coatings4.5.1 Diamond as a coating material4.5.2 Diamond coatings4.5.3 Diamond-like carbon coatings4.6 Combined coatings4.6.1 Multicomponent coatings4.6.2 Nanocomposite coatings4.6.3 Multilayer coatings4.6.4 Duplex treatments4.6.5 Adaptive 043113165 Coating characterization and evaluation5.1 The requirements5.2 Coating characteristics5.2.1 The surface5.2.2 Thickness5.2.3 Adhesion5.2.4 Morphology5.2.5 Composition5.2.6 Wettability5.2.7 Residual stress5.3 Property characterization and evaluation5.3.1 Roughness5.3.2 Thickness5.3.3 Mechanical evaluation5.3.4 Physico-chemical evaluation5.3.5 Tribological evaluation5.3.6 Accelerated testing5.3.7 Industrial field testing5.3.8 Standardization3196 Coating selection6.1 Problems of selection6.2 Traditional approaches6.3 A methodology for coating selection6.4 Selection rules6.5 Design guidelines6.6 Expert systems6.7 Closing knowledge gaps3637 Applications7.1 General7.2 Sliding bearings7.2.1 Description of the application7.2.2 Improvements by surface 342347355359360363365367371377379382383384384385

xContents7.3 Rolling contact bearings7.3.1 Description of the application7.3.2 Improvements by surface coatings7.4 Gears7.4.1 Description of the application7.4.2 Improvements by surface coatings7.5 Tools for cutting7.5.1 Description of the application7.5.2 Tool wear7.5.3 Improvements by surface coatings7.5.4 Cutting test results7.6 Tools for forming7.6.1 Description of the application7.6.2 Improvements by surface coatings7.7 Erosion and scratch resistant surfaces7.7.1 Description of the application7.7.2 Improvements by surface coatings7.8 Oscillating contacts7.8.1 Description of the application7.8.2 Improvements by surface coatings7.9 Magnetic recording devices7.9.1 Description of the application7.9.2 Improvements by surface coatings7.10 Microcomponents7.10.1 Description of the application7.10.2 Improvements by surface coatings7.11 Biomedical applications7.11.1 Description of the application7.11.2 Improvements by surface coatings7.12 Future NDIX A441APPENDIX B473REFERENCES477SUBJECT INDEX549

PREFACEThis book gives a comprehensive description of thin surface coatings, their behaviour and potentialuses in tribological applications. The deposition techniques, tribological mechanisms, properties ofcoatings, characterization, evaluation and selection methodology in addition to application examplesare described and discussed. One aim of the book has been to bring together, systematically in a singlevolume, the state-of-the-art knowledge on tribological coatings.The book is the result of very fruitful research cooperation between the tribology research group atthe VTT Technical Research Centre of Finland in Helsinki and the Surface Engineering researchgroup at the University of Sheffield in the UK. It brings together accumulated knowledge both oncoating processes and on the tribology of coatings.The authors published the first edition of the book in 1994. The contents in this second edition arethoroughly revised and expanded by more than 50%. Completely new sections have been writtenrelated to deposition of composite and nanostructured coatings, nanotribological contact mechanisms,modelling and simulation of stresses in coated surfaces, fracture mechanics analysis, wear productgeneration, lubricated contact mechanisms, diamond-like carbon and molybdenum disulphide coatings, coating selection and application examples. In the earlier text, we tried to take into account themost important published works at that time which covered over 1500 in all and we cited over 800 ofthese. Since then, the field has seen a remarkable growth in published output, and in the present bookmore than 3000 publications were scrutinized, of which about 1700 are cited herein.As in the earlier book, we have tried to present the contents in a logical, easily assimilated, manner.We have retained the systematic structure of the earlier book, which has remained appropriate androbust, despite the many developments over the ensuing years.Kenneth HolmbergAllan MatthewsHelsinki and SheffieldSeptember 2008xi

ACKNOWLEDGEMENTSA great number of people, including colleagues, friends and family, have through the years supportedand encouraged the authors with their work in the field of coatings and tribology. We are most gratefulto all of them and express our sincere thanks.The authors also extend their thanks to Mr Erkki Makkonen for meticulous preparation of theillustrations.The financial support of the Swedish Academy of Engineering Sciences in Finland and the VTTTechnical Research Centre of Finland is gratefully acknowledged.xii

rRlength of crack or deformation, or afterarea, e.g. contact area or projected area of indentationcontact area contributed by deformed asperitiesload support area of the coatingdebris contact areaload support area of the substratehalf contact length or beforeconstant or crack lengthcontentdiameter or indentation diagonal length or crack depthYoung’s modulus of elasticity or elastic modulusreduced modulus of elasticity, 1/E0 ¼ 0.5((1 v21)/E1 (1 v22)/E2)friction forcematerial parameter in elastohydrodynamic lubrication, G ¼ a E’, or toughnessstrain–energy release ratehardnessfilm thickness parameter, H0 ¼ h/R0film thickness or indentation displacementconstantwear rate, K ¼ V/w s, or fracture toughness or stress intensity factorcoefficient of wear, K0 ¼ V H/w slength of contactcritical loadindentation size effect (ISE) indextorquenumber of cyclespressureradiusradiusxiii

adius of conformity, 1/R0 ¼ (1/R1) (1/R2)centreline average value (CLA or Ra) for the roughness of the surfaceRockwell hardness (c-scale)relative humiditymaximum height of irregularitiespeak-to-valley height value for the roughness of the surfaceten points height value for the roughness of the surfacedistanceshear strength or slope of unloading curvedummy variabletemperature or transition zonevelocitydisplacement in x-directionspeed parameter, U ¼ (ho u0 )/(E0 R0 ) or elastic energy storedvelocitydisplacement in y-directionvolume of worn or deformed materialnormal loadload per unit lengthload parameter, W ¼ w/(E0 R0 l), or workdistance in x-direction or length of distancedistance in y-direction or length of distanceyield stress or correction factordistance in z-directioncrack shape factorGreek symbolsa pressure exponent of viscosity or coefficient of thermal expansion or empiricalcontactb percentage of asperity contact area under compressiong Boussinesq function or surface energyG deviator stress or unit area3 strain or indenter geometry constantz standard deviation of asperity height distributionr crack spacingh absolute dynamic viscosityQ anglec empirical interface parameterl specific film thickness, l ¼ hmin/R0 am coefficient of friction, m ¼ F/wv Poisson’s ratios stress or strength in tensions stress or strength in shearsa shear strength within asperity adhesion areaSubscriptsa adhesion or asperity or abrasivec coating or critical or contact

ompositedeformation or debriseffectivefilm or finalfatiguehydrogenHertziancounter, i ¼ 1, 2, ., NinterfaceinterfacejunctionKnoopmelting or hydrostaticmaximumminimumambientploughing or peakradial or rough or reduced or residualresidualsubstratethermalupper surfaceVickersvon Misesyieldxv

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CHAPTER 1IntroductionTribology is the field of science and technology dealing with contacting surfaces in relative motion –which means that it deals with phenomena related to friction, wear and lubrication.Tribology played a central role in early technological evolution, even in ancient times. Reducingfriction by using wheels made it possible for humans to move further and faster, and the lubrication ofsleds made it possible to transport building blocks and raise large structures. Together with goodtribological engineering knowledge, metal as a construction material and oil as a lubricant eventuallysmoothed the path for the modern industrial revolution, and allowed new inventions like high strengthand low friction bearings and gears that were key components in high power machinery, as describedby Dowson (1998), Ludema (2001) and Holmberg (2004).In modern industrialized societies there is a growing need to reduce or control friction and wear forseveral reasons, for example to extend the lifetime of machinery and bio-systems, to make enginesand devices more efficient, to develop new advanced products, to conserve scarce material resources,to save energy, and to improve safety.Historically these aims have been achieved by design changes, selecting improved bulk materials,or by utilizing lubrication techniques. Bulk material changes might involve applications with ceramics or polymers. The lubrication techniques would include the use of liquid lubricants such asmineral or synthetic oils or solid lubricants such as molybdenum disulphide.Recently, tribologists have made increasing use of another approach to friction and wear control –that is to utilize surface treatments and coatings. This has led to, and to some extent been fuelled by,the growth of a new discipline called surface engineering. This growth has been encouraged by twomain factors. The first has been the development of new coating and treatment methods, whichprovide coating characteristics and tribochemical properties that were previously unachievable. Thesecond reason for the growth in this subject area has been the recognition by engineers and materialsscientists that the surface is the most important part in many engineering components. It is at thesurface that most failures originate, either by wear, fatigue or corrosion. The surface has a dominantinfluence on lifetime cost and performance, including machinery maintainability.The surface may also have other functionally important attributes, not confined to mechanical orchemical properties, such as thermal, electronic, magnetic and optical characteristics that influencethe choice of surface material. The retention of these physical surface properties is clearly essentialthroughout the life of the product. It is a further reason why surface durability enhancement by appropriate coating selection is critical to any product’s effectiveness, and therefore its saleability in themarketplace.Like all products, mechanical components and tools are today facing higher performancerequirements. The use of surface coatings opens up the possibility for a material design in which thespecific properties are located where they are most needed. The substrate material can be designed forstrength and toughness while the coating is responsible for the resistance to wear, corrosion andthermal loads, and the achievement of the required frictional characteristics.Tribologists developed an understanding of the behaviour of surfaces in contact, providing a theoretical basis for the prediction of the desirable attributes of surfaces, even before fully optimizedcoatings were available.It is against this background that new coating and treatment methods are being developed, and arealready having a significant impact. Devices and bearing systems which operate under near-vacuum1

2Coatings Tribologyconditions, as in space mechanisms or satellites, or engine components operating under hot corrosiveand erosive conditions, as in aero gas turbines, could not function without advanced tribologicalcoatings.At present, hard coatings such as titanium nitride, titanium carbide and aluminium oxide arecommonly used on cutting tools in the manufacturing industry. Chromium nitride and molybdenumdisulphide coatings are used on metal forming tools. Very hard but also low friction diamond-likecarbon coatings are deposited for wear protection on magnetic storage devices produced for computers. Optical lenses are produced with hard erosion-resistive thin transparent coatings. Variouscarbon-based coatings are used on components in the automotive industry to reduce energy consumption. The coatings in some applications are deposited as multicomponent coatings, multilayers,gradient layers, superlattice structures and duplex-treated surfaces with various material combinationsas shown by Hogmark et al. (2001).While coatings for the applications cited are in commercial use, there are many others that are stillat a developmental stage. In this book we set out the background to present developments in tribological coatings, emphasizing the newer processes. We place this in the context of current thinkingon the theories and experimental findings relating to the use of surface coatings in tribology.We shall take as our definition of tribological coatings those which are sufficiently thin that thesubstrate material plays a role in the friction and wear performance. Thus, we exclude coatings whichare so thick that there is little or no substrate influence on the tribological behaviour – the coating ineffect acts as a bulk material. Weld deposits are a typical example of such thick coatings that havebeen excluded from in-depth study.With this definition of tribological coatings we focus on solid surface films that are typicallyin a thickness range of 0.1–10 mm. New deposition techniques and improved nanotribologicalunderstanding have made it possible to produce tribologically effective solid surface films even as thinas 1–5 nm for magnetic storage device applications (Bhushan, 1999a; Wang et al., 2005).The coating processes can conveniently be divided into four generic groups – gaseous, solution,molten and solid – depending on the state of the depositing phase (Rickerby and Matthews, 1991a).Our definition of tribological coatings means that we shall concentrate mainly on the gaseous stateprocesses, which are attracting considerable scientific and commercial interest. In particular, the maincoatings that we shall consider will be those deposited by plasma-assisted techniques, since those canprovide excellent adhesion to the substrate and the dense coating structural morphologies which areneeded for tribological applications.A general design appraisal of the tribological requirements on contact with coated surfaces can beformulated as follows:1. The initial coefficient of friction, the steady-state coefficient of friction and the friction instabilitymust not exceed certain design values.2. The wear of the coated surface and that of the counterface must not exceed certain design values.3. The lifetime of the system must, with a specified probability, be longer than the required lifetime.The lifetime limit of the system may be defined as occurring when at least one of the earlierrequirements is not maintained.To meet the tribological requirements, the coated surface must possess a suitable combination ofproperties, for example in terms of hardness, elasticity, shear strength, fracture toughness, thermalexpansion and adhesion. As shown in Fig. 1.1 we can distinguish between four different zones, eachwith different properties which must be considered.The properties required by the substrate and by the coating involve material strength and thermalattributes determined by their composition and microstructure as well as the porosity and homogeneity of the material. At the interface between them, the adhesion and shear strength of the junction isimportant. At the surface of the coating the chemical reactivity and the roughness must be consideredin addition to the shear strength.

Introduction3Fig. 1.1. Tribologically important properties in different zones of the coated surface.A primary problem in surface design is that many desired properties, such as good adhesion at thecoating/substrate interface and no surface interactions with the counterface, or high hardness and hightoughness of the coating, cannot easily be obtained simultaneously. Increased hardness and strength isoften concomitant with decreasing toughness and adherence. For this reason the final coating design isalways a compromise between many different technical requirements on the properties of the coatingsystem and the economical requirements on the deposition of the coating on to products.The factors that determine the coating material properties are the constitution of the materialsystem and the fabrication parameters, such as the coating process and the thickness, as shown inFig. 1.2. Both of these determine the microstructure of the coating, including, for example, its density,grain size, grain boundaries and grain orientation.The whole coated surface system with its properties and functional parameters can be considered asa composite system to be optimized to gain maximum benefit (Rickerby and Matthews, 1991a, b).This, in essence, specifies the fundamental philosophy of surface engineering, which has been definedby Melford (1991) as ‘the design of surface and substrate together, as a system, to give a cost-effectiveperformance enhancement of which neither is capable on its own’.The selection criteria for choosing one surface engineering technique over another are complex. Itis often not realized that the properties of the bulk material may be impaired by the coating or surfacetreatment. A second important point is that, to get maximum benefit from a coating, a redesignprocedure may be necessary. This further complicates an already complex task for the design engineerfaced with the prospect of selecting from the many coatings available.There have been various attempts to devise a selection procedure for surface coatings. Originallycoatings were seen as a last resort solution to problems which had their roots in poor design or poor

4Coatings TribologyFig. 1.2. Examples of factors influencing material properties of coated surfaces (after Holleck, 1986).material selection. Frequently, companies would adopt what James (1978) describes as a positiveselection approach; that is, a coating will be tried, and if it works it will be used. However, this oftenresults in better solutions being rejected by default.Progressive elimination of all feasible solutions is to be preferred for many reasons, even thoughit is more time consuming. The discipline inherent in this approach encourages the acquisition ofinformation, rather than the assumption of knowledge, and the investigation of alternative ways ofsolving minor problems obstructing highly desirable solutions.It is important to make expert advice available at the earliest opportunity. If freedom to contributeto the original design and to feed advice and suggestions before the design is finalized is permitted, thesurface may play a significant role in producing a part with superior performance at a reasonable cost.Thus tribological coatings need not necessarily be viewed as an additional cost feature; they oftenallow the use of a lower-grade, cheaper substrate material while providing improved quality andperformance.The potential offered by computer-based modelling, simulation and coating selection tools coupledwith the new coating processes, makes possible the solution of problems to which tribologists previously had only theoretical solutions. The holistic modelling of a coated tribological contact is a verycomplex task. However, the rapid increase in computer processing capacity in the last few decadestogether with improved software tools for modelling has brought us to the point where realistic modelbased optimization of a coated surface for tribological use is a reality, as shown by Holmberg et al.(2003).It has been known for many years that tribochemical reactions at the contact interface are critical inmany tribological systems. Often these lead to the formation of stable compounds, after a period ofrubbing, which then control the ensuing friction and wear behaviour. This occurs in applications asdiverse as cutting and lubricated sliding. In the latter case steps are often taken to encourage theformation of specific compounds at the interface, for example by the use of extreme pressure additives. Advanced surface engineering techniques allow the design and production of such compoundsas surface layers, prior to in-service use, thereby ensuring effective control of the tribological system.Furthermore, not only is the sliding mechanism improved by such possibilities, it can also bepossible to modify the thermal behaviour, altering both thermal and chemical diffusion effects. This inturn leads to the possibility of improving the efficiency of machines, with the consequential economicadvantages of good tribological design.The economical impact of friction and wear on society is huge. It has been estimated that theeconomic cost of wear and friction in USA exceeds US 100 billion per annum (Blau, 2008). Improved coatings and selection procedures lead to decreased friction and wear. This will enable improved efficiency over a longer lifetime and provide a considerable reduction in overall energy

Introduction5consumption, not to mention reductions in costs caused by in-service failure or maintenance downtime. An important objective for tribological coatings should be the achievement of extended andpredictable lives, and ideally non-catastrophic failure modes.The potential of tribological coatings is extensive, and it is hoped that this book will assist designersand others who specify coatings to do so more effectively and more widely. The book is structured insuch a way that individual sections and chapters can be read, free-standing, in their own right. Themain aim, however, is to provide a text that covers the important aspects of coatings tr

TRIBOLOGY AND INTERFACE ENGINEERING SERIES Editor Brian Briscoe (UK) Vol. 27 Dissipative Processes in Tribology (Dowson et al., Editors) Vol. 28 Coatings Tribology – Properties, Techniques and Application

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