Effect of nano-Cu-loaded graphene fillers on tribological properties of PTFE based composite coatings

Abstract The Polytetrafluoroethylene(PTFE)-based composite coating has been widely used in the tribology field due to the high strength of graphene(GNS) and the self-lubricating property of PTFE. However, the weak interfacial bonding between GNS and PTFE inhibits the tribological performance of PTFE-based composite coatings. In this study, the composite coating is in situ fabricated by loading Cu nanoparticles on the GNS surface, and the microstructure, bonding, friction, and wear properties of the composite coating were investigated. The results showed that the interfacial bond strength, friction, and wear properties of Cu@GNS-PTFE coating are higher than those of pure PTFE and GNS-PTFE coating. Compared with the PTFE coating, the Cu@GNS-PTFE coating with the optimal ratio(5%) can increase the bond strength by 24.6% and reduce the wear rate by 42.2%. The lubrication mechanism of the Cu@GNS-PTFE coating is the Cu nanoparticle can increase the interfacial bonding property of GNS and PTFE from both mechanical interlocking and chemical activity, which can promote the synergistic lubrication of GNS and PTFE, and provide a theoretical basis for the further application of PTFE and GNS.