Tribological Behavior of Atmospheric Plasma-Sprayed Cu-Ni Coatings

Atmospheric plasma-sprayed (APS) copper-nickel-based coatings are commonly used for the prevention of fretting wear of components in aerospace engines. In this study, Cu-Ni alloy was deposited using plasma spraying on different substrate materials such as stainless steel, carbon steel, and aluminum alloy to investigate the influence of the substrate materials as well as the performance (mechanical and tribological behavior) of the coatings. Microstructural studies revealed a homogeneous microstructure with the presence of splats for coatings deposited on each substrate. The porosity and microhardness of coatings deposited on each substrate were found to be within the range of (1.22 ± 0.27-1.65 ± 0.33%) and (117 ± 10-136 ± 23 HV_0.05), respectively. The tribology results also showed an increase in the frictional coefficient for each substrate from 0.41 at 25° to 0.73 at 300 °C. However, a steady state was not obtained at 450 °C. Similarly, the wear rates of coatings for each substrate increased from 300 to 450 °C test conditions, with no significant wear obtained at 25 °C. The results showed that the substrate materials had no significant effect on the performance of the coatings, as the thickness, porosity, surface roughness, and microhardness of coatings for each substrate material were comparable with no remarkable difference.