低维材料协同增强AZ91D镁合金表面纳米复合电沉积

Synergistic Enhancement of AZ91D Magnesium Alloy Surface via Nanocomposite Electrodeposition with Low-Dimensional Materials

摘要:

为提高镁合金表面综合性能，采用纳米复合电沉积技术在AZ91D镁合金表面制备添加零维材料纳米金刚石（ND）和一维材料碳纳米管（CNTs）的Ni基复合层。结果表明，ND与CNTs复配的协同作用改善了沉积层的组织结构并提升其综合性能。ND作为异质形核核心，促进Ni晶粒沿(111)面择优取向生长，降低Ni基沉积层表面粗糙度，并提升其组织均匀性与致密性；CNTs的高比表面积与优异导电性进一步优化了沉积层组织结构与性能。两种碳基纳米材料复配表现出优异的协同增效作用：ND的晶粒细化效应与CNTs的导电增强作用相辅相成，使沉积层在结构致密性、晶粒取向稳定性以及界面结合强度等方面显著优化，进一步提高了耐磨性与耐蚀性。当ND与CNTs添加量分别为12、0.15 g/L时，沉积层组织结构均匀致密，硬度达1212.7 HV，摩擦系数降至0.34，自腐蚀电流密度降至1.458×10^–7 A·cm^–2（较镁合金基体降低3个数量级），抗铜绿假单胞菌性能良好，抑菌率达90%。本研究为低维材料协同增强高性能镁合金表面复合沉积层提供了理论依据和工艺参考。

Abstract:

To enhance the comprehensive performance of magnesium alloy surfaces, Ni-based composite layers added with zero-dimensional material nano-diamond (ND) and one-dimensional material carbon nanotubes (CNTs) were prepared on the surface of AZ91D magnesium alloy by nano-composite electrodeposition technique. The results show that the synergistic effect of the combination of ND and CNTs optimizes the microstructure of the deposited layer and enhances its comprehensive performance. ND, as a heterogeneous nucleation core, promotes the preferred orientation growth of Ni grains along the (111) plane, 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 are 12 and 0.15 g/L, respectively, the microstructure of the deposited layer is uniform and dense, the hardness reaches 1212.7 HV, the coefficient of friction decreases to 0.34, the self-corrosion current density decreases 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 is good. The antibacterial rate is as high as 90%. This study provides a theoretical basis and process reference for the synergistic reinforcement of composite deposition layers on high-performance magnesium alloy surface with low-dimensional materials.