High temperature tribological properties of the high-hardness wear-resistant Cu-Ni-Al-Sn coatings produced by laser cladding

The high-hardness wear-resistant Cu-Ni-Al-Sn coatings were fabricated by laser cladding, and the effect of Sn content on the microstructure, hardness and high temperature tribological behavior of the coatings was investigated. The results revealed that the hardness of the coatings increased from 177.6 to 674.0 HV0.3 due to the strengthening of Cu9NiSn3, FeNi and NiSn precipitations. In addition, Sn plays an important role in improving the high temperature tribological properties of the coatings. At 25–200 ℃, Sn can form a low shear-stress film to reduce the friction coefficient and wear rate. When the temperature exceeds 300 ℃, a tribo-oxides layer containing SnO2, CuO and Fe2O3 forms on worn surfaces, which play a role in improving the tribological properties.