Dry sliding friction and wear behaviour of TiC-based ceramics and consequent effect of the evolution of grain buckling on wear mechanism

Abstract

In this study, the dry sliding tribological behaviour of TiC-based ceramics against alumina is elucidated. Monolithic TiC as well as TiC-SiC composites were successfully densified by spark plasma sintering (SPS) using TiC and SiC powders as starting materials. Friction tests were performed using a pin-on-disk-type friction tester wherein alumina was used as counterpart material in an unlubricated condition at room temperature. The friction coefficient for the TiC-based ceramics dry sliding against alumina all initially increased and attained steady state after the first 200 s. The coefficient of friction in the case of monolithic TiC attained steady state earlier than the composites and exhibited the lowest friction coefficient. The specific wear rate of the TiC-based ceramics increased with increasing SiC content; it was lowest when sliding against monolithic TiC. The increase in wear rate in the composites is linked to grain buckling induced fracture owing instability arising from residual compressive stresses inherent in the composite due to mismatch in thermal expansion coefficients between TiC and SiC. The wear mechanism in general appears to be primarily dominated by third-body wear triggered by grain fracture and subsequent grain pull-out.