Design and evaluation of tribological coatings

The use of coatings to improve the tribological properties of components such as tools for metal cutting and forming, and machine elements e.g. sliding bearings, seals and valves is constantly increasing. This paper presents tribological design considerations of coating composites and recommends methods and techniques for their evaluation. It is aimed both for those involved in scientific development of coatings and for the practising tribology engineer. Current design concepts of coatings for tools and machine elements are exemplified together with successfully coated components. Techniques for evaluation of some of the more important fundamental and tribological properties will be presented and several examples are given mainly with thin physical vapour deposition (PVD) coatings. The evaluation techniques can be utilised both in coatings selection and in development of new coatings. Some recent trends and speculations about the future end the paper.