Friction and wear behaviours of in situ reduced graphene oxide reinforced zirconia ceramic

The tribological behaviour of zirconia composites reinforced by in situ reduced graphene oxide (IrGO) was investigated by a rotating ball-on-plate configuration at room temperature, and was followed by a comparison with composites reinforced by pre-reduced graphene oxide(rGO). The results indicate that both the friction and wear resistance of ceramics increase with the incorporation of graphene oxide (GO). IrGO is better for enhancing the tribological performance of zirconia than rGO. The wear rate decreases by up to one order of magnitude (from 2.33 x 10(-5)mm(3).N-1.m(-1) to 4.66 x 10(-6) mm(3.)N(-1.)m(-1)) with 0.5 wt% GO. A protective tribofilm containing reduced graphene oxide forms at wear surfaces of ceramics, and the protruding-out of rGO is more pronounced. The main wear mechanism changes from severe delamination to plastic deformation and micro-cracking with increasing GO content. The analysis of wear tracks for ceramics with GO additives by Raman mapping reveals a decrease in the tetragonal-monoclinic phase transformation after sliding wear, which is regarded as the intrinsic reason for the improved wear resistance.