Wear and Corrosion Resistance of Cold-Sprayed Cu-Based Composite Coatings on Magnesium Substrate

The applications of magnesium-based alloys are often limited by their poor corrosion and wear resistance performance. The aim of this study is to improve the performance of magnesium alloys by using metal-ceramic coatings. Cu-Ni/Al2O3 and Cu-Zn/Al2O3 coatings were deposited by cold spray. Their microstructure, microhardness, tribological, and corrosion behavior were compared with those of Cu-Al2O3 coatings. The results showed that the Cu-Al2O3 coatings exhibited higher microhardness, lower wear rate, and better corrosion resistance than the Mg alloy substrate, but their antifriction performance was not ideal. Adding Ni or Zn to the Cu-Al2O3 coating resulted in a denser coating with lower porosity. Ni increased the microhardness of the Cu-Al2O3 coating but did not improve its antifriction performance or wear resistance, while Zn increased the microhardness, antifriction performance, and wear resistance of the Cu-Al2O3 coating. The corrosion resistance of the Cu-Al2O3 coating was enhanced by adding Ni, which improved the compactness of the coating, in contrast to the addition of Zn, as the rapid corrosion of Zn resulted in formation of loose corrosion products without protective effect. Thus, such modification of Cu-Al2O3 coatings should be based on application requirements.