Improvement of anti-oxidation capability and tribological property of arc ion plated Ag film by alloying with Cu

Ag–Cu alloy film was deposited by arc ion plating (AIP). Atomic oxygen (AO) irradiation experiments were conducted using a ground AO simulation facility. The structure, morphology, composition and tribological property of the Ag–Cu alloy film before and after AO irradiation were investigated and compared with Ag film using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscope (XPS) and ball-on-disk tribometer, respectively. In depth XPS analysis clearly shows that the affected thickness of Ag–Cu alloy film was greatly reduced and the oxidation product was mainly Ag2O, but AgO and Ag2O in case of pure Ag film. As a result, the Ag–Cu alloy film exhibited better AO resistant behaviors, and showed a stable friction and low wear after the AO irradiation. The AO resistant behaviors of the Ag–Cu alloy film were discussed in terms of the film microstructure.