Preparation and tribological behavior of copper matrix composites reinforced with nickel nanoparticles anchored graphene nanosheets

Graphene nanosheets (GNS) anchored with nickel nanoparticles (Ni@GNS) are designed and used as the reinforcement to synthesize self-lubricating copper matrix composites (Ni@GNS/Cu). The tribological behavior of Ni@GNS/Cu are investigated as a function of Ni@GNS content and applied load and further compared with those of bare sintered copper and copper matrix composites enhanced with bare GNS (GNS/Cu) to elucidate the effect of Ni@GNS reinforcement, especially the interfacial bonding between graphene and copper matrix on the tribological performance of copper matrix composites. The incorporation of Ni@GNS with up to 2 wt. % significantly reduces the friction and improves wear resistance of copper matrix. Ni@GNS/Cu composites also exhibit lower frication and wear rate than GNS/Cu with the same GNS content. The improved tribological performance can be attributed to the formation of stable and compact GNS-rich tribolayer on the worn surface of Ni@GNS/Cu composites along with their higher hardness due to the improved interfacial bonding of Ni@GNS and Cu matrix.