化学镀锌工艺对镁合金表面电镀Al-Zn复合镀层的影响

Effect of Electrotess Zinc Plating Process on Al-Zn Composite Coating on Magnesium Alloy Surface

为了提高镁合金的耐蚀性,采用电镀铝-化学镀锌工艺在其表面制备了Al-Zn复合镀层。通过镀层形貌观察及物相分析考察了其组成结构,采用电化学方法研究了主盐浓度、络合剂浓度、槽液温度对镀层耐蚀性的影响。结果表明:采用电镀铝-化学镀锌工艺得到的Al-Zn复合镀层平整度、均匀性优异,镀层与基体结合牢固。最佳施镀工艺参数为ZnSO_(4)·7H_(2)O质量浓度40g/L,K_(4)P_(2)O_(7)·3H_(2)O质量浓度150g/L,化学镀液温度为50℃。与基体试样相比,在最佳工艺参数条件下施镀后,试样的腐蚀速率大幅降低。该工艺能够实现很好的电镀效果和防腐蚀性能,具有一定的工业价值。

In order to improve the corrosion resistance of magnesium alloys,an Al-Zn composite coating was prepared on the alloy surface by the process of electroplating aluminum-electroless zinc plating.Composition and structure of the coating were investigated through observation of coating morphology and phase analysis.The influence of main salt concentrations,complexing agent concentrations and bath temperature on the corrosion resistance of the coating was studied by electrochemical methods.The results showed that the Al-Zn composite coating obtained by the process of electroplating aluminum-electroless zinc plating had excellent flatness and uniformity,and the coating was firmly bonded to the substrate.The optimal plating process parameters were ZnSO_(4)·7H_(2)O with a mass concentration of 40g/L,K_(4)P_(2)O_(7)·3H_(2)O with a mass concentration of 150g/L,and the temperature of the electroless plating solution was 50℃.Compared with the base sample,the corrosion rate of the sample was greatly reduced after plating under the best process parameter conditions.This process could achieve good electroplating effect and anti-corrosion performance,and had certain industrial value.