影响Zn-Ni-P合金镀层中Ni和P含量的因素

Factors Affecting Content of Ni and P in Electroplated Zn-Ni-P Alloy Coating

为促进Zn-Ni-P合金电沉积层在汽车、造船、航空、电子等工业中的应用,研究了氯化物电镀Zn-Ni-P体系中各共沉积金属离子总浓度、镍锌离子摩尔比、H3PO3、Jc、pH值及温度等因素对镀层Ni和P含量的影响。试验得到的最佳条件:71g/L氯化锌,101g/L氯化镍,180g/L氯化钾,30g/L硼酸,15g/L亚磷酸,电流密度2A/dm2,pH值3.0,温度30℃。用5%NaCl溶液进行浸泡腐蚀试验,试验结果,Ni含量为13%～15%和P含量为0.7%～0.9%的Zn-Ni-P合金镀层的耐蚀性约为纯锌镀层的8倍。

In order to promote the application of Zn-Ni-P alloy in automobile,shipbuilding,aviation,and electronics industries,the influences of several factors on the content of Ni and P in electroplated Zn-Ni-P alloy coating were investigated.Thus the total concentration of metallic ions,Ni2+/Zn2+ and H3PO3,and Jk,pH value and temperature were studied with respect to their effects on the content of Ni and P in the alloy coating.Moreover,the corrosion resistance of the alloy coating was examined making use of immersion tests in aqueous solution of 5% NaCl.Results showed that the optimized bath was composed of 71 g/L zinc chloride,101 g/L nickel chloride,180 g/L potassium chloride,30 g/L boric acid,and 15 g/L H3PO3,while the optimized plating parameters were suggested as current density of 2 A/dm2,pH value of 3.0,and temperature of 30 ℃.The Zn-Ni-P alloy coating containing 13%~15% Ni and 0.7%~0.9% P had anticorrosion life as much as eight times of that of zinc coating.