Tribological Properties and Wear Mechanisms of Laser Cladded Cu–Mo Coatings at 25–500 °C

Abstract

Surface modification is the major means to improving the wear resistance of copper alloys. In this study, Cu–Mo coatings were prepared on Cu–Cr–Zr alloy by laser cladding, and the high-temperature tribological properties against 7075 aluminum alloy were explored. The results show that the coatings are a two-phase structure of Mo encapsulated in Cu-mesh. The hardness and resistivity of the coatings are 61–73 Hb and (3.2–6.3) × 10−8 Ωm, respectively. The wear resistance of the coatings is determined by the hardness, which is related to the Mo content at lower temperatures, and it is controlled by the tribo-oxides layer composed of copper and molybdenum oxides at higher temperatures. As the temperature increases, the main wear mechanism of the coatings changes from abrasive wear to adhesive wear.