Electrical sliding friction wear behaviors and mechanisms of Cu–Sn matrix composites containing MoS2/graphite

Abstract

Cu–Sn matrix composites were prepared by vacuum hot press sintering technique with the addition of MoS2, graphite and a mixture of MoS2/graphite, respectively. The friction wear behaviors and contact resistance of the three composites under different currents were investigated and compared. The friction film formed on the friction surface was analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The wear mechanism and the evolution of friction film composition of the composites under different currents were revealed. The results showed that MoS2 and graphite had synergistic lubrication effects. The Cu–Sn-Graphite-MoS2 composite exhibited low wear rates and the lowest and most stable contact resistance. MoS2 could effectively promote the formation and integrity of the friction film and optimize the friction wear performance. With the increase of current, the graphite content in the friction film rose, which helped to reduce the oxidation and consumption of the friction film. The increase in current accelerated the shedding of lubricating particles and the softening of lubricating film, making the lubricating film denser and reducing the oxidation depth.