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

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.