Laser cladding Ni-based WC/MoS2 composite coatings: Particle competition mechanism and tribological performance

Abstract

To develop a highly wear-resistant coating with self-lubricating characteristics, this study reports the use of laser cladding to fabricate WC/MoS₂ composite coatings on the surface of 65Mn steel plates. Here, we investigated the effects of different laser powers and MoS₂ contents on the phase composition, phase distribution, microstructure, and friction/wear properties of the coatings, focusing on heat and element competition mechanisms, as well as the wear mechanism of the Ni-based WC/MoS₂ composite coatings. The results show that compared with MoS₂, WC remains disadvantaged in terms of heat competition in the molten pool. However, during MoS₂ thermal decomposition, the free Cr atoms in the pool are also captured, not only changing the type and morphology of the M_xC_y carbides and inhibiting WC heat damage but also resulting in a decreased content of M_xC_y carbides within the coating. When a significant amount of Cr_xS_y gathers on the coating surface, a stable and continuous lubricating film is formed, allowing the coating to balance the wear resistance with lubrication.