2,2-联吡啶光亮剂对5,5-二甲基乙内酰脲无氰镀银性能的影响

Effect of 2,2-Bipyridine as a Brightener on Properties of Silver Coating Electroplated in Cyanide-Free 5,5-Dimethyl Glycolylurea Bath

已有的光亮剂用于5,5-二甲基乙内酰脲为配位剂的无氰镀银体系,存在镀层形貌不好、外观不亮的缺陷,同时其组成也较复杂。为此对过去已用的光亮剂进行了筛选,最后确定以2,2-联吡啶作为无氰镀银体系的光亮剂。采用稳态极化曲线测量研究了加入2,2-联吡啶前后镀液的特性,通过SEM,XRD等测试技术对镀层形貌及结构进行了表征。结果表明,2,2-联吡啶光亮剂的加入可以增大镀液的极化,改变银镀层的晶体取向,显著细化晶粒,获得光亮的银镀层,使银镀层的耐磨性、防变色能力得到增强。

Based on screening of currentlyavailable brighteners used for cyanide-free Ag electroplating in plating bath with 5,5-dimethyl glycolylurea as the complexing agent,2 ,2-bipyridine was selected as the brightener for Ag elec-troplating. The characteristics of the plating baths with and with-out 2,2-bipyridine were evaluated,and the morphology and mi-crostructure of electroplated Ag coatings were analyzed by meansof scanning electron microscopy and X-ray diffraction. Results indicate that 2,2-bipyridine as the brightener is able to acceler-ate polarization of the plating solution,change orientation of elec-troplated Ag coating and increase the brightness,wear resistance and anti-tarnishing capability of Ag coating.