Tribological study of polytetrafluoroethylene lubricant additives filled with Cu microparticles or SiO2 nanoparticles

The SiO2 nanoparticles and polyvinyl pyrrolidone (PVP) modified Cu microparticles were synthesized and characterized. The surface morphologies of the polytetrafluoroethylene (PTFE) particles and the filled PTFE particles were also analyzed. PTFE particles were modified by filling of Cu microparticels or SiO2 nanoparticles and their dispersion stability in base oil was also observed. The anti-friction and anti-wear performance of pristine and modified PTFE particles as lubricant additives was studied by a four-ball tester. Our results show that the additives can significantly improve the anti-friction and anti-wear performance of the base oil. This is due to the self-lubricating property of PTFE particles and the formation of tribochemical reaction films. A tribological model of the pristine and modified PTFE particles was proposed to explain the lubrication mechanisms.