Influence of Al2O3 and h-BN on Wear and Corrosion Performance of IN625 Nickel-Based Coating

IN625 offers high-temperature oxidation resistance, wear resistance, and stable chemical properties. To improve the corrosion and wear resistance of the Q345B steel surface, two types of metal matrix composites (IN625 + 1% Al2O3 and IN625 + 1% h-BN) were applied to the substrate surface using the laser cladding process. This study analyzed the hardness, electrochemical corrosion, friction, and wear properties of both the laser-clad specimens and the substrates. The results show that (1) the hardness and wear resistance of the fusion-coated coating were significantly improved compared with the base material. Notably, the hardness increased by 19%, and the coefficient of friction decreased by 41% compared with the IN625 + 1% h-BN coating. Furthermore, the hardness and wear resistance of the IN625 + 1% h-BN coating were superior to those of the IN625 + 1% Al2O3 coating, attributed to the formation of eutectic compounds such as NiB and Ni2B in the dendritic region. (2) The corrosion resistance of the IN625 + 1% Al2O3 coating exceeds that of the IN625 + 1% h-BN coating and is also superior to that of the substrate. This improvement is primarily attributed to the addition of Al2O3, which enhances solid solution strengthening within the dendritic crystals of the fused-coating layer, reduces the percentage content of inclusions, and elevates the corrosion resistance of the coatings.