氯化钾镀锌层三价铬黑色钝化工艺

通过单因素试验、正交试验优选出一种适合氯化钾镀锌层三价铬黑色钝化的工艺,研究了钝化液组分和钝化条件对钝化膜性能的影响。采用醋酸铅点滴试验、电化学测试、扫描电子显微镜对三价铬黑色钝化膜的耐蚀性及表面形貌进行了检测。结果表明:镀锌层经三价铬黑色钝化后再进行封闭处理,不仅外观乌黑油亮、膜层均匀,而且其耐蚀性也显著提高。

Process for Black Trivalent Chromium Passivation of Galvanizing Coating Obtained in Potassium Chloride Solution

The optimal processing conditions for black trivalent chromium passivation of galvanizing coating obtained in KCl solution were established based on single-factor test and orthogonal test. The morphology of the passivation coating was observed using a scanning electron microscope. The effects of the composition of passivation fluid and technological parameters on the performance of the passivation coating were investigated. The corrosion resistance of as-prepared passivation coating was evaluated using dropping corrosion test of lead acetate and electrochemical test. It was found that black trivalent chromium passivation of the galvanizing coating plus follow-up sealing produced a uniform and bright black surface with significantly increased corrosion resistance.