Effect of Interfacial Microstructure on Mechanical and Tribological Properties of Cu/WS2 Self-lubricating Composites Sintered by Spark Plasma Sintering

In this study, Cu/WS2 self-lubricating composites are fabricated by spark plasma sintering. Interfacial microstructure and its effect on mechanical and tribological properties are investigated. High sintering temperature at 850 °C promotes decomposition of WS2 and its following interfacial reaction with Cu to form Cu0.4W0.6 nanoparticles and Cu2S, enhancing mechanical properties as well as wear resistance of the composites. But the destruction of WS2 leads to a high friction coefficient. On the contrary, for the composites sintered at 750 °C, a nanoscale diffusion zone forms at the Cu/WS2 interface. WS2 lubricant retains its lamellar structure. The composite shows excellent self-lubrication performance, with a low friction coefficient of 0.16. However, its mechanical properties are low, and the wear rate is one magnitude higher.