钢铁直接电镀用新型无氰一价铜镀液的研究

Study on a novel cyanide-free copper(I)-based bath for direct electroplating on steel substrate

开发了可应用于钢铁表面直接电镀的无氰一价铜镀液体系。通过电化学测试研究了采用硫脲作为配位剂对亚铜离子电沉积的影响,并通过百格试验、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分析了所得铜镀层的结合力、表面形貌、元素组成和相结构。结果表明,硫脲可与一价铜形成稳定的配合物,令亚铜离子的析出电位显著负移,避免钢铁直接电镀时发生铜铁置换反应。该体系镀液在不低于60°C的温度下具有较宽的工作电流密度范围,并且阴、阳极电流效率均高于95%,能够直接在钢铁表面电沉积得到平整、结晶细致、纯度高、结合力优异的铜镀层。

A cyanide-free copper(I)-based bath for direct electroplating on steel substrate was developed.The effect of thiourea as complexing agent on the electrodeposition of copper(I)ion was studied electrochemically.The adhesion,surface morphology,elemental composition,and phase structure of the electroplated copper coating were characterized by cross-cut testing,scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS),and X-ray diffraction(XRD),respectively.The results showed that thiourea could form a stable complex with Cu(I)ion,resulting in a much more negative deposition potential of Cu(I)ion,and avoiding the displacement reaction between copper and iron when conducting the electrodeposition of copper directly on steel substrate.The given bath had a wide range of working current density at a temperature not lower than 60°C.Both cathodic and anodic current efficiencies of the bath are higher than 95%.A smooth,compact,fine-grained,highly pure,and well-adhered copper coating could be electrodeposited directly on steel in the given bath.