Layer-by-layer analysis: Tribological behaviour of Ni60A coating on copper substrate prepared by plasma cladding

Abstract

To further clarify the characteristics of plasma-cladded Ni60A coating on copper, the microstructure and wear behavior were analyzed layer by layer. Along the depth direction, the coating can be divided into three regions according to the difference of microstructure: upper, middle and bottom. The phase composition in different regions was the same (including γ-(Cu, Fe, Ni), Cr₂₃C₆, CrB and Ni₃Si), and there was no obvious difference in the volume fraction of strengthening phases (Cr₂₃C₆ and CrB). Due to the stronger load-bearing capacity of larger-size strengthening phases, the wear resistance of middle region was slightly higher than that of upper region. However, the high copper content in bottom region led to a decrease in hardness and resistance to plastic shear, which significantly reduced the wear resistance (2.3 times lower than upper region). Chemical composition had a greater impact on the wear resistance than size and distribution uniformity of strengthening phases.