Friction and wear mechanism analysis of the electro brush plating Ni-Mo alloy

The Ni-Mo coating as a replacement for hard chrome plating has gained popularity due to its low environmental pollution. This thesis aims to investigate the characteristics of a Ni-Mo alloy brush coating on a 45# steel base material using the brush plating process. The composition of the plating solution was varied to analyze the effects on the surface morphology, microstructure, hardness, and wear resistance of the Ni-Mo coating. The experimental results demonstrate that the surface morphology of the brush coating is significantly influenced by the composition of the plating solution. As the concentration of nickel sulfate and sodium molybdate varies, the coating exhibits a clear preferential growth tendency. Higher nickel sulfate concentration leads to the growth of coating grain along the (111) crystal plane, while higher sodium molybdate concentration encourages the growth of coating grain along the (220) crystal plane. Increased nickel sulfate concentration results in refined coating grains, while increased sodium molybdate concentration causes more distortion and dislocation of the coating layer. It was observed that the brush plating coating of Ni-Mo alloy, with a nickel sulfate concentration of 400–500 g/L and a sodium molybdate concentration of 25–30 g/L, exhibits not only good surface morphology but also higher micro-hardness and wear resistance. Overall, the analysis of the effects of plating composition on the characteristics of Ni-Mo coating is crucial in developing a high-quality and effective coating for industrial applications.