“两步”法镁合金化学镀镍的研究

以硫酸镍为主盐,研究了镁合金"两步"化学镀镍工艺·利用扫描电子显微镜(SEM)、能谱分析(EDS)和X射线衍射仪检测镁合金"两步"化学镀膜的表面形貌、成分及相结构,利用增重法研究了化学镀速度,并通过锉刀试验评价镀层与基体的结合力·结果表明,在直接化学镀4min后可以实现以硫酸镍为主盐的第二步化学镀镍;"两步"化学镀层为高磷非晶态,表面光亮,耐蚀性良好;且镀层与基体结合力好·"两步"化学镀不仅其镀速快于单一直接化学镀,而且可以优化镁合金化学镀速度与相结构的结合,有效地调整镀层磷含量分布;以硫酸镍为主盐"两步"化学镀能降低镁合金化学镀成本,提高其实用性·

Two-Steps Electroless Nickel Plating of Magnesium Alloys

The two-step electroless nickel plating (TSENP) of magnesium alloys using NiSO4·6H2O as the main salt was introduced. The morphology, composition and phase structure of TSENP coatings were investigated by means of Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). In addition, the coating growth rate was tested through weighing by electro-balance and the bonding strength between coating and substrate was evaluated through file-checking. The results showed that the plating of magnesium alloys with NiSO4·6H2O solution as the main salt, i. e., the 2nd step should be carried out successively 4 minutes after the direct land electroless nickel plating (DENP). It was verified that the coating growth rate of single DENP is lower than that of TSENP, the sheeny TSENP coating is of high-phosphorus amorphism with higher corrosion resistance and bonding strength than DENP coating. The P content in weight is effectively distributed in the coating. In short, TSENP will not only decrease the cost but improve the applicability.