This study used coaxial laser cladding technology to prepare NiCr composite coatings with different contents of Mo/CrB₂ dual-phase reinforcement on the surface of 304L stainless steel. The results show that the coating is mainly composed of a γ-Ni solid solution and hard boride phases such as CrB and MoB, and its phase composition exhibits a certain regularity with increasing Mo content. The addition of an appropriate amount of CrB₂ can form uniformly distributed hard reinforcing phases while avoiding a sharp increase in coating brittleness due to excessive borides. On this basis, the addition of Mo can further optimize the distribution of borides, regulate the phase composition, and compensate for the insufficient crack resistance of coatings reinforced solely with CrB_2. The addition of Mo and CrB₂ refines the grain structure and increases the coating hardness, reaching a maximum hardness of 633.1 HV_0.1, more than double that of pure NiCr. Friction and wear tests indicate that the friction coefficient and wear rate of the coating initially decrease and then increase with increasing Mo/CrB₂ content. When the Mo content is 10 wt.%, and the CrB₂ content is 20 wt.%, the coating exhibits the lowest wear rate of 5.6×10^-6 mm³/N·m, approximately 84% lower than that of the pure NiCr coating. The improved wear resistance is attributed to the high hardness of the coating, effectively resisting plastic deformation during friction, while the composite oxide film formed on the worn surface provides a self-lubricating effect, changing the wear mechanism from adhesive wear to mild abrasive and oxidative wear. However, excessive CrB₂ (greater than 20 wt.%) increases coating brittleness, and excessive Mo leads to the precipitation of a brittle μ phase and causes coarsening of the structure; both conditions are prone to spalling under frictional stress, thereby deteriorating the coating wear resistance.

Laser cladding, NiCr coating, dispersion strengthening, solid solution strengthening, oxidative wear, lubricating film