Microstructure and Tribological Properties of Cu-15Ni-8Sn Coating Sprayed by HVAF

A Cu-15Ni-8Sn coating was fabricated on the surface of 2205 duplex stainless steel using the high-velocity air fuel (HVAF) spraying technique. The microstructure of the coating was characterized by advanced electron microscopies. Hardness tests and wear performance evaluations under oil-lubricated conditions were conducted on the coating. The results indicate that the coating is consisted of nano gains with the grain sizes ranging from 60 to 80 nm and the alloying elements completely dissolving into the Cu matrix. The coating has a hardness of HRC 29.2. Under the conditions of evaluating the wear performance, the coating exhibits a stable friction coefficient of 0.05 ~ 0.14 and a wear rate of (1.66 ~ 3.89) × 10⁻⁸ mm³/mm, much better than the wear performance of bulk Cu-15Ni-8Sn materials with the same hardness and nano precipitates. Further analysis on the worn surfaces and debris was conducted, and the wear mechanism of the coating was discussed. Overall, the Cu-15Ni-8Sn solid-solution nanocrystalline coating demonstrated excellent mechanical and tribological properties, indicating its potential for application in part repair, performance enhancement, and service life extension.