Abstract:To enhance the comprehensive performance of magnesium alloy surfaces, Ni-based composite layers with zero-dimensional material ND (nano-diamond) and one-dimensional material CNTs (carbon nanotubes) added were fabricated on the surface of AZ91D magnesium alloy by nano-composite electrodeposition technology. The synergistic effect of the combination of ND and CNTs improved the microstructure of the deposited layer and enhanced its comprehensive performance. Research shows that ND, as a heterogeneous nucleation core, promotes the preferred orientation growth of Ni grains along the (111) surface, reduces the surface roughness of Ni-based deposition layers, and enhances their microstructure uniformity and density. The high specific surface area and excellent electrical conductivity of CNTs further optimize the microstructure and properties of the deposited layer. The combination of two carbon-based nanomaterials exhibits an excellent synergistic effect: the grain refinement effect of ND and the electrical conductivity enhancement effect of CNTs complement each other, significantly optimizing the deposited layer in terms of structural density, grain orientation stability, and interfacial bonding strength, further enhancing wear resistance and corrosion resistance. When the addition amounts of ND and CNTs were 12 g/L and 0.15 g/L respectively, the microstructure of the deposited layer was uniform and dense, the hardness reached 1212.7 HV, the coefficient of friction decreased to 0.34, the self-corrosion current density decreased to 1.458×10-7 A·cm-2 (three orders of magnitude lower than that of the magnesium alloy matrix), and the resistance to Pseudomonas aeruginosa was good. The antibacterial rate is as high as 90%. This study provides a theoretical basis and process reference for the synergistic reinforcement of high-performance magnesium alloy surface composite deposition layers with low-dimensional materials.