硅溶胶改性水性丙烯酸树脂对镀锌三价铬钝化膜的封闭作用

Sealing Effects of Silica Sol Modified Waterborne Acrylic Resin on Chromium Trivalent Passivation Film of Galvanized Steel

为提高镀锌三价铬钝化膜的耐腐蚀性能,研究硅溶胶改性水性丙烯酸树脂对镀锌三价铬钝化膜的封闭效果。通过Tafel极化曲线、电化学交流阻抗谱(EIS)、盐水浸泡实验和中性盐雾实验(NSS)测试镀锌钝化膜封闭后的耐腐蚀性能和200℃高温处理后的热稳定性,采用SEM,FT-IR及TGA对封闭膜层的形貌及特性进行表征。结果表明:与未改性和未封闭的镀锌钝化膜相比,硅溶胶改性的镀锌钝化封闭剂可以显著提高钝化膜的阻抗值,有效减缓镀锌钝化膜在盐水中的腐蚀速率,延长耐盐雾腐蚀时间,且硅溶胶的引入可以显著提高镀锌钝化膜封闭后的耐热性能。

In order to improve the corrosion resistance of the trivalent chromium passivation film on galvanized steel, the effects of silica sol modified waterborne acrylic resin on the passivation film were studied. The corrosion resistance and the thermal stability of the passivation film were measured by Tafel polarization curve, electrochemical impedance spectroscopy （EIS）, salt water immersion test and neutral salt spray test （NSS）, and the morphology and properties of the film were characterized by SEM, FT-IR and TGA. The results show that compared with the unmodified and unsealed passivation film on galvanized steel, silica sol modified sealant can significantly improve the resistance of the passivation film, effectively slow down the corrosion rate of the passivation film in 3.5%NaCl solution, and extend the enduring time under salt spray test; and the heat resistance of the passivation film can be improved remarkably by the introduction of silica sol.