Effect of Ni@MoS₂ addition on the microstructure and tribological performance of β-phase matrix composite coatings

The NiCr-Cr₃C₂/Ni@MoS₂/Ti6Al4V self-lubricating and wear resistant composite coatings were successfully fabricated on the surface of Ti6Al4V via laser cladding. The effect of Ni@MoS₂ addition on the microstructure of the composite coating was investigated through a combination of first-principles calculations and experimental characterization. Subsequently, the intrinsic relationship between the microstructural evolution of and the wear properties of composite coatings was elucidated. The results demonstrated that the composite coatings with varying Ni@MoS₂ dosages consisted of β phases matrix, along with in-situ synthesized TiC, Ti₂Ni, Ti₂S, and TiS₃ phases. First-principles calculations and experimental results indicated that the sufficient in-situ synthesis of a lubricating phase (TiS₃) with two-dimensional layered structures and a strengthened phase (Ti₂S) effectively inhibits adhesion wear and enhances surface bearing capacity. Consequently, the composite coating containing 20 wt% Ni@MoS₂ exhibits reduced coefficient of friction (COF) and wear rates simultaneously.