Friction and wear characteristics of containing a certain amount of graphene oxide (GO) for hot-pressing sintered NiCr-WC-Al2O3 composites at different temperatures

The NiCr-WC-Al2O3 composites with the addition of graphene oxide (GO) were fabricated by powder metallurgy technique. The effects of graphene oxide on the microstructure and tribological properties of the composites from room temperature to 700 °C were investigated. The tribofilms formed on the rubbing surfaces and their effects on the tribological properties of composites at different temperatures were analyzed by SEM, XRD, and EDX. The results show that the sintered composites were mainly composed of Ni-based solid solution, Al2O3, CrxCy and WC, the optimized amount of graphene oxide in the composites is up to 3 wt % to balance the lubricity and mechanical properties of composites. The tribological properties of composites were improved by adding graphene oxide, the friction coefficient and wear rate of composites decreases with the increasing of graphene oxide contents, especially in high temperature ranges and the composites with addition of 3 wt% graphene oxide (GO) exhibits the lowest friction coefficient (0.41) and wear rate (1.0 × 10−5 mm3/Nm) at 700 °C. The tribofilms composed of new compounds Ni2Al18O29, NiCr2O4 and NiWO4 which formed on worn surface of the composites at high temperature is responsible for the reduction of friction and the wear rate of composites.