Microstructure and Tribological Properties of Self-Lubricating Graphite/Ni60 Composite Coatings Prepared by Laser Cladding

Ni60 superhard alloy with the additions of graphite solid lubricants was successfully prepared on 45 carbon steel substrate by means of laser cladding. The quality of coating was relatively high and had metallurgical bonding with the substrate. The morphology of laser cladding layer was observed by SEM, composition analysis was applied by EDS. Elevated temperature frictional behaviors of graphite/Ni60 composites coatings were investigated on MMG-10 wear machine. The results showed that the friction coefficient of graphite/Ni60 composite coating was obviously decreased from 0.55 to 0.20 with increasing temperature. The wear mechanism transformed from adhesion to oxidation with the increase of temperature. The graphite/Ni60 composite coating material showed the optimum self-lubricating property at 500°C.