高耐蚀性镀锌层三价铬蓝白色钝化工艺

Blue-white trivalent chromium passivation process on zinc coating with high corrosion resistance

开发了一种环保的镀锌层三价铬蓝白色钝化工艺。研究了钝化液中CrCl3·6H2O、Na3C6H5O7、NaNO3、钴盐等成分及pH和温度等工艺参数对钝化膜外观和耐蚀性的影响。蓝白钝化的最佳工艺条件为:CrCl3·6H2O 48g/L,NaNO3 20g/L,Na3C6H5O7 18g/L,钴盐18g/L,室温,pH1.5,钝化时间8s。采用最佳工艺所得钝化膜为光亮、均匀的蓝白色,表面平整、致密,耐蚀性优于镀锌层。

An environment-friendly trivalent chromiumblue-white passivation process for zinc coatings wasdeveloped. The effects of bath components such as CrCl3·6H2O, Na3C6H5O7,NaNO3 and cobalt salt, andprocess parameters including pH and temperature on theappearance and corrosion resistance of passivation coatingwere studied. The optimal process conditions are as follows：CrCl3·6H2O 48 g/L, NaNO3 20 g/L, Na3C6H5O718 g/L, cobaltsalt 18 g/L, room temperature, pH 1.5, and passivation time8 s. The passivation coating obtained under the optimalprocess conditions is bright and blue-white, uniform, smoothand compact, and has better corrosion resistance than zinccoating.