An initial approach to the link of multi-layer coatings contact stresses and the surface engineered gears

The tribological properties in surface contact can be markedly improved by coating the surface with soft or hard layers according to practical applications. Rapid developments in surface engineering technologies have made available many surface engineering systems to combat diverse component degradation problems and to meet the ever increasing demands for combined properties in modern machinery operating under ever more severe conditions. Designers thus have many surface engineering technologies to select from in the design of components. Therefore, numerical modelling is urgently required for surface engineering to assist engineers in their design of components with the surface and substrate as a system. The present paper attempts to introduce a numerical approach for the contact behaviour of multi-layer systems and establish an initial link between the contact stresses and performance of the surface engineered gears. Experimental tests have been carried out on untreated, TiN coated, plasma nitrided and duplex treated steel gears. Here duplex treatment indicates plasma nitrided steel gear with TiN coating. The model has also been applied in powertrain transmission titanium gears as well as polymer composite gear failure mechanisms.