Enhanced of friction and wear properties for TiC/TC4 coating based on the precipitation of the lubricating and strengthening phases through laser cladding of Cr–WS2–Ni60 powder

To address the shortcomings of TiC/TC4 titanium alloy-based ceramic coatings in wear resistance and high-temperature stability, the TiC/TC4 coating was reinforced by introducing two types of mixed powders, Ni60-WS 2 and Cr-Ni60-WS 2 , onto the surface through laser cladding technology. In the cladding layer of the WS 2 -Ni60 coating, in addition to the original unmelted white blocky TiC phase, new granular W 2 C and strip-like TiNi phases were formed. After Cr was added, fine Cr particles, flake-like TiS 2 phase, granular Cr 3 C 2 phase and uniformly distributed TiC were further generated. The hardness of both coatings showed a gradient distribution across the composite coating zone, heat-affected zone, and near-substrate zone. The highest hardness which was 3 times that of the substrate was observed at 0.25 mm from the surface. When the laser power was 1200 W, the friction coefficients at room temperature and 500°C of the Cr-Ni60-WS 2 coating were 0.32 and 0.30 respectively. The formation of the lubricating phase TiS 2 , the strengthening phase Cr 3 C 2 , and the uniformly distributed TiC phase was the main reason for the excellent wear resistance. Lower power caused incomplete phase decomposition, leading to adhesive wear. Higher power results in delamination wear due to thermal stress and phase coarsening.