SURFACE ENGINEERING - ITS CURRENT AND FUTURE-IMPACT ON TRIBOLOGY

The role of surface engineering in the war against wear has been well recognized in recent years, not only because wear and friction are surface-related phenomena, but also because of the growing commercial maturity of a wide range of cost-effective surface technologies. In the present paper, the basic principles of surface engineering and its impact on tribology are illustrated principally through the technology of thermochemical processing of ferrous materials. The success of surface engineering to combat wear is demonstrated by the current application of such surface technologies as thermochemical treatments and ceramic coatings to a variety of engineering components. However, surface engineering is not simply about using one of the available surface technologies to modify the surface properties. Surface engineering is essentially about design. Hence, under situations where components are subjected to complex external loadings, more than one surface technology needs to be employed in order to produce the required combination of properties to combat the loadings. This philosophy of designer surfaces is discussed in the paper, and illustrated through detailed theoretical and experimental studies on the tribological behaviour of plasma-nitrided and combined plasma-nitrided and PVD TiN-coated low-alloy steel.