Structure and Formation Mechanism of Surface Film of Ag-MoS2 Composite during Electrical Sliding Wear

Ag-MoS2 composite brushes were fabricated by means of powder metallurgy process. The composite was detected by the method of XRD after sintering, and the worn surface of the brush was analyzed by XPS after the wearing experiments with current. Results showed that the components of the composite didn't change during sintering, but the surface components of it changed upon wearing and some matters such as MoO3 and MoO2 were produced. At the same time, Cu2O, CuO and Cu2S were detected due to the adhesion transfer of elemental Cu from the slipping ring to the brush surface and the reaction between the elemental Cu and the ambient air molecules. During electrical sliding wearing, the surface film can reduce the friction coefficient and be beneficial to the frictional performance of the material.