浸锌液中甘油对提高铝浸锌层上电镀层结合力的作用

考虑到甘油的保湿作用,提出在浸锌液中添加甘油,以期改善铝合金大工件浸锌后时而出现的上部镀层结合力不良的现象。利用pH试纸液痕法、时间-电位曲线测试及热震-划格法,分别研究了采用加入不同浓度甘油的浸锌液一次浸锌后,铝试片上滞留液膜的分布、浸锌层的稳定电位变化及后续镀层结合力。结果表明:加入甘油后,浸锌液膜分布均匀,甘油质量浓度为20g/L时可有效防止浸锌层上部因液膜干燥而被氧化,从而保证后续镀镍层的结合力。

Effect of Glycer in in Zincate Solution on Improving Cohesive Force of Electroplating Coating on Aluminum Substrate

Addition of glycerin in zincate solution was first reported in consideration of its moisturizing function to improve the adhesive force of upper electroplating nickle layer.Method of observing liquid mark on pH test paper,time-potential curve measurement and thermal shock followed by cross cut test were utilized to study the retained liquid film distribution,the potential development of zincate film and adhesive force of electroplating nickle coating on aluminum substrate respectively after one time zincate immersion with different concentration of glycerin in zincate solution.It indicated that the retained liquid film became well-distributed when 20 g/L glycerin was added and oxidation of the upper zincate layer caused by liquid film drying was conquered to guarantee the well-adhesion of successive electroplating coat.