Effects of WC on the Microstructure, Wear and Corrosion Resistance of Laser-Deposited CoCrFeNi High Entropy Alloy Coatings

Abstract

Wear and corrosion resistant properties of high entropy alloy coatings (HEAC) on H13 steel are of particular interest for industrial applications. The CoCrFeNi HEA/WC composite coatings (HEACC) developed in this study were successfully prepared by incorporating 10–40 wt.% WC into a matrix of CoCrFeNi HEA using laser cladding on an H13 steel substrate. Phase transformation, microstructure evolution, microhardness, wear and corrosion resistance of CoCrFeNi HEACC were investigated. According to the results, all CoCrFeNi HEACC exhibited higher wear and corrosion resistance than the H13 steel substrate. Wear resistance of CoCrFeNi HEACC first increases and then decreases with an increase in the concentration of WC particles, and the lowest coefficient of friction and the shallowest depth of wear groove were observed after adding 30 wt.%. Grain refinement strengthening and second-phase particle strengthening may contribute to enhanced hardness and wear resistance of coatings with WC additions. In addition, all the CoCrFeNi HEACC exhibited improved corrosion resistance. In particular, an addition of 10 wt.% WC helped to significantly improve the corrosion resistance and ease of passivation of CoCrFeNi HEACC.