AZ31镁合金化学镀工艺研究

Investigation of Electroless Plating on AZ31 Magnesium Alloys

研究了在挤压态AZ31镁合金表面直接化学镀镍工艺。通过扫描电镜(SEM)和X射线衍射技术(XRD)对镀层组织结构及形貌和磷含量进行了检测分析,并对化学镀层表面进行了显微硬度和镀层与镁合金基体的结合力测试。结果表明:得到的N i-P镀层均匀、致密、无明显缺陷,其平均沉积速度约为0.32μm/min,平均显微硬度约为566HV,所含磷的质量分数为9.77%。前处理过程中的酸洗步骤使镁合金基体产生略为粗糙的表面,从而改善了镀层和基体之间机械咬合的作用,增加了镀层的结合力,结合力约为22N。

Direct electroless Ni-P plating on the AZ31 magnesium alloys in a plating bath containing nickel carbonate was investigated. The morphology and microstructure of the electroless Ni-P coating were studied by SEM and XRD. The electroless Ni-P coating was compact and no obvious defects. The hardness value of the Ni-P coatings was 566 HV and the phosphorus content of this coating was about 9.77 wt%. The deposition rate of the electroless Ni-P alloys was about 0.32 μm/ h. The acid pickle pretreatment on the AZ31 magnesium alloy substrate provides surface pits to act as sites for mechanical interlocking to improve adhesion between the coating and the substrate. The adherence of them is 22No