Tribo-behaviour of APS and HVOF sprayed WC-Cr3C2-Ni coatings for gears

The tungsten-carbide coatings could be employed to minimise failures of gears due to excessive wear in hostile operating atmospheres. In this work, WC-Cr3C2-Ni powder was deposited on the SS 316L substrate using APS and HVOF processes. The deposited coatings were characterised and investigated for the effects of dissimilar counter bodies. The unidirectional sliding experiments were conducted on the ball-on-disc tribometer (ASTM G99-95a). The variable contact pressure was applied to simulate the tangible effect of contact stress variation during the dry sliding in the gears. The wear mechanisms depicted that the wear is in the mild regime and better durability of both coatings. The results of tribo-testing and analysis of results by ANOVA confirmed that contact pressure and hardness of counter body are significant factors influencing friction and wear. Furthermore, the relation between contact surface temperature and adhesion of debris to the surface has been studied.