Effects of Different Laser Powers on the Structure and Properties of In Situ TiC-Enhanced Ni-Based Coatings

In situ TiC-enhanced Ni-based coating was prepared on the surface of 45 steel by laser cladding technology, the effects of different laser powers on the phase component, microstructure, microhardness and wear resistance of the coating were systematically investigated. The results show that the coating phase component contains TiC, CrB, Ni₃B, M₂₃C₆, M₇C₃ and Fe-Ni solid solutions at different laser powers. As the laser power increases, the microstructure changes from coarse columnar and dendritic crystals to finer columnar and dendritic crystals. After evaluating the microhardness of the samples with different laser powers, the highest microhardness of the composite coating was obtained at a laser power of 1600 W, which was 401.4 HV. Friction wear results revealed that the wear rate of the coating decreased with increasing laser power, and the wear rate was minimized at 1600 W, showing excellent wear resistance. This is attributed to the diffuse strengthening and grain refinement of the hard phase, which improves the hardness and wear resistance of the coating.