Characteristics of WC reinforced Ni-based alloy coatings prepared by PTA + PMI method

Abstract The WCP/Ni60A coating and the Ni@WCP/Ni60A coating were clad on the surface of Q235 steel by plasma transferred arc welding (PTA) and plasma melt injection (PMI) method. The microstructure, hardness and wear resistance of the clad coatings were investigated respectively. The results showed that, the PTA + PMI method can effectively avoid the burning and sinking of WC particles. Both the coatings had relatively uniform microstructure, which were mainly composed of γ-Ni, Cr23C6, CrB, WC, W2C, and Cr7C3-typed compounds. The average hardness of the matrix for the WCP/Ni60A and Ni@WCP/Ni60A coatings were 1006.27 ± 40.25 HV and 905.77 ± 36.23 HV respectively. The wear mechanism of both coatings was mild adhesion wear, in contrast with the severe adhesion wear of substrate. Moreover, attributed to slighter dissolution of WC, the Ni@WCP/Ni60A coating possessed better wear resistance, whose wear mass loss was only 1/30 that of the Q235 substrate.