聚乙烯亚胺对置换镀金过程中镍基体腐蚀的影响

Effect of Polyethylene Imine on Corrosion of Electroless Nickel Substrates during Immersion Gold Plating

摘要:

通过XRF、SEM、XPS、开路电位、极化曲线、电化学阻抗谱及红外漫反射等方法，分析了聚乙烯亚胺对置换镀金过程中镍基体腐蚀的影响原因。结果表明：聚乙烯亚胺降低了置换镀金初始时沉积速率，而对长时间施镀镀速的影响较小；聚乙烯亚胺降低了金层Ni、O元素的含量；该添加剂能够在镍、金表面吸附，而且优先在金表面吸附，并加速了镍表面氧化物的溶解速率。聚乙烯亚胺使化学镀镍层表面活性趋于一致，减轻了镍基体的过度腐蚀现象。

Abstract:

The effects of polyethylene imine on the corrosion of electroless nickel substrates during immersion gold plating were investigated by XRF, SEM and XPS in combination with open-circuit potential, polarization curves, electrochemical impedance spectrum and infrared (IR) reflection spectrum analysis. The results show that the polyethylene imine decreases the initial deposition rate while it has little effect on the longer deposition rate. The polyethylene imine decreases the concentrations of Ni and O in the gold coating. Moreover, it is also revealed that this additive could be adsorbed on the nickel or gold surface, and the adsorption on gold surface is stronger than that on nickel. The polyethylene imine improves the dissolution of the passivating film which is formed on the surface of the substrate and reduces the difference between activity/passivity of adjacent features of the surface. As a result, in the presence of this agent, the localized dissolution of nickel will be reduced and nickel contained in the substrate composition will be dissolved almost uniformly.