Abstract:In this work, Cu/Ag/Graphite coating was deposited on steel substrates by plasma spraying process. The tribological behavior of Cu/Ag/Graphite coating under different currents has been tested using a HST-100 pin-on-disc friction and wear tester in an air atmosphere with humidity of about 50%. The coating microstructure, phase composition,worn surface and debris were characterized by field emission scanning electron microscope (FESEM), energy dispersive X-ray spectrum (EDS) and X-ray diffraction (XRD). The results show that Cu/Ag alloy forms a continuous metal network in as-received coating and the deposited graphite particle demonstrates an obvious orientation direction parallel to the substrate. With the increasing current from 0A to 50A, it was found that the wear rate of Cu/Ag/Graphite coating is increased and related closely with the pin contact pressure and sliding velocity. It is of interesting to note that the friction coefficient of Cu/Ag/Graphite coating was not affected by the increasing currents under the same contact pressure and velocity in this work. Graphite transfer film and oxidization layer were the main reasons for stable electrical sliding process. Under no current applied, the wear mechanism was abrasive wear; however, the electrical wear would become the main wear mechanism with the increase of current intensity during electrical sliding process.