Effect of Mo₂S Addition Amount on Microstructure and Properties of MoS₂/Ni60A Solid Self-lubricating Coating

MoS₂/Ni60A solid self-lubricating coating was prepared on 35CrMnSi steel substrate by laser cladding with Ni60A alloy powder and MoS₂ powder as cladding materials. The effects of MoS₂ addition amount (mass fraction of 1%, 3%, 5%, 7%, 9%) on the phase composition, microstructure, microhardness and tribological properties of the coating were investigated. The results show that the coatings with different MoS₂ addition had good surface formability and were metallurgical by bonded with the substrate. The main phase of the coatings were MoS₂, γ-Ni, NiS, Cr₂B. The microstructure of middle and upper position was mainly composed of rod-shaped, fishbone-shaped and radial dendrite. The microstructure of the bottom and fusion line was composed of planar and columnar crystals. With the increase of MoS₂ addition, the microhardness of the coating decreased and the wear rate increased, and the friction coefficient decreased first and then increased. When the addition of MoS₂ was 3%, the friction coefficient of the coating reached the lowest of 0.43, and a complete solid self-lubricating film was formed on the worn surface; The plough furrow was less and the main wear mechanism was slight abrasive wear.