热浸镀锌层表面偏钒酸盐转化膜

Metavanadate conversion coating on the surface of hot-dip galvanized coating

在热浸镀锌试样表面获得了一层均匀、完整的偏钒酸盐转化膜。成膜溶液成分及工艺条件为:NaVO35g/L,pH1.3,温度30°C,时间30min。对比研究了偏钒酸盐转化膜和铬酸盐转化膜的耐蚀性能。结果表明,偏钒酸盐转化膜由Zn、O、V等元素组成,热浸镀锌层经偏钒酸盐转化处理后电化学阻抗和极化电阻增大,腐蚀电流密度减小,耐蚀性明显提高且超过了铬酸盐转化膜。

A uniform and complete metavanadate conversion coating was obtained on the surface of hot-dip galvanized coating. The bath composition and conditions are as follows： NaVO3 5 g/L, pH 1.3, temperature 30 ℃ and time 30 min. The corrosion resistance of metavanadate conversion coating and chromate conversion coating was compared. The results showed that the metavanadate conversion coating is mainly composed ofZn, 0 and V elements. The polarization resistance and electrochemical impedance values of hot-dip galvanized coating are increased while decreased after treating with corrosion current density is metavanadate. The corrosion resistance of metavanadate conversion coating is greatly improved and exceeds that of chromate conversion coating.