Effects of WS2 and Cr3C2 addition on microstructural evolution and tribological properties of the self-lubricating wear-resistant CoCrFeNiMo composite coatings prepared by laser cladding

In this work, a self-lubricating wear-resistant CoCrFeNiMo composite high entropy alloy (HEA) coating was fabricated on the 304L stainless steel through laser cladding technology. The WS2 and Cr3C2 were added to the CoCrFeNiMo HEA to improve the tribological properties. The phase composition, microstructure evolution, and tribological properties of the composite coatings were systematically studied. The experimental results show that the CoCrFeNiMo HEA composite coating exhibits good tribological performance from room temperature to 800 °C under the synergistic effect of multiple lubrication mechanisms. The sulfide particles formed in-situ in the coating can promote the formation of a friction film on the worn surface, obviously reducing the friction coefficient of the composite coating below 600 °C. While the addition of Cr3C2 can reduce the effect of WS2 on the mechanical properties of the HEA matrix. During the high-temperature friction process, the smooth oxide glaze layer generated on the worn surface of the composite coating make it also shows a low friction coefficient.