Microstructure and Friction and Wear Property of Nano-WC Reinforced Ni-Based Coating

In order to improve the surface hardness and wear resistance of 12CrMo steel, Ni60 reinforced coatings containing the nano-WC powder mass fractions of 0, 10%, 20%, 30%, and 10% were prepared on the surface of substrate by semiconductor laser in this paper. The microstructure and phase composition of samples were analyzed by OM, SEM, EDS, and XRD. The mechanical property and friction and wear property were tested using a digital microhardncss tester and a high temperature friction and wear tester. The results show that the nano-WC reinforced Ni60 coating surface is well-formed. The microstructure of the enhanced coating is strip, dcndritic, fishbonc, block, and granular. The phase is dominated by austcnitic Ni-Fe, part of nano-WC remains, part of W2C new phase is formed. A series of complex compounds, such as Cr23C6, M6C, Cr7C3, Crb, and NiW, arc generated in the coating. The maximum microhardncss of the nano-WC reinforced coating is 1256 HV0.2, which is about 50% higher than that of the Ni60 alloy coating. The minimum wear volume of reinforced coating is 1.29 mm(3), which is only 1/7 of Ni60 alloy coating; the average friction coefficient of the reinforced coating is as low as 0.275, while that