Effect of Cu content on microstructure evolution and tribological behaviors of Ni60 composite coatings on 45# steel by laser cladding

The Ni60-Cu composite coatings with varying Cu contents were fabricated by laser cladding technology. The effects of Cu addition on the microstructure, microhardness, and tribological behaviors were explored systematically. The results revealed that the composite coatings were primarily consisted by gamma-Ni, FeNi3, Cr7C3 , Ni3Si, Cu, and Fe-Ni-B. The addition of Cu was instrumental in enhance the tribological behavior at room temperature and 600 degrees C compared with the 45# steel substrate. Moreover, S2(Ni60-5 %Cu) coating showed the best compressive tribological properties, especially at 600 degrees C, it has the lowest friction coefficient of 0.267 and wear rate of 4.90 x 10(-5) mm(3)/N.m. The Cu played the role of tribo-transfer film and oxidation double-layered selflubricant at room temperature and 600 degrees C, respectively.