碱性镀锌层三价铬黑色钝化、封闭一体化后的性能

Corrosion Resistance and Heat Resistance of Alkaline-System Zinc Coatings after Passivation with Trivalent Chromium Black Film in Association with Sealing by Silicofluoride

为了进一步探讨碱性镀锌件三价铬黑色钝化膜的耐蚀性能及耐热性能,将纳米氟硅化合物添加到三价铬黑色钝化液中,同步进行钝化和封闭。采用中性盐雾试验及电化学技术分析了纳米氟硅化物含量对钝化、封闭膜的质量、耐蚀性能和耐热性能的影响。结果表明:纳米氟硅化合物填充在整个三价铬形成的骨架中,弥补了三价铬钝化无自修复能力的不足;当纳米氟硅化合物含量为2.0 g/L时,溶液稳定,膜的耐腐蚀性能和耐热性能最好。

Nanoscale silicofluoride was introduced into trivalent chromium black passivation fluid to conduct simultaneous passivation and sealing of Zn coating obtained from an alkaline bath.The effect of nanoscale silicofluoride content in the passivation fluid on the quality as well as corrosion resistance and heat resistance of the Zn coating was investigated based on neutral salt-spray test and electrochemical test.Results indicated that nanoscale silicofluoride was incorporated into the skeleton of trivalent chromium passivation film thereby providing the film with self-repair capacity.Particularly,the passivation fluid containing 2.0 g / L nanoscale silicofluoride had good stability,and corresponding trivalent Cr passivation film after sealing treatment exhibited the best corrosion resistance and heat resistance.