镀锌层三价铬黑色钝化膜的耐蚀性能

摘要

An environmental friendly trivalent chromium passivation solution without Cr6＋ was prepared and a suitable sealing for the solution was choosed to study corrosion resistance of the passive film on galvanized steel sheet formed in this solution.The anti-corrosion property and morphology of the passive film were analyzed by Pb（CH3COO）2 solution spot test,tafel polarization curves,EIS and scanning electron microscopy.The results indicate that the obtained black passive film not only had an appearanced as good as that after Cr6＋treatment but also complemented the problem without self-healing ability for the Cr3＋ passivation.The corrosion resistance can be increased significantly after treatment with sealant.%制备了一种环保、不含六价铬的三价铬黑色钝化液,选择适当的封闭剂,研究其在镀锌层表面钝化后的耐腐蚀性能。通过醋酸铅点滴试验、塔菲尔极化曲线测试、电化学阻抗测试检测钝化膜的耐蚀性及采用扫描电子显微镜观察其表面形貌。结果表明：镀锌层表面经三价铬黑色钝化后再进行封闭处理,弥补了Cr3＋钝化后无自愈能力的缺点,显著提高了镀锌层钝化膜的耐腐蚀性能,而且达到了Cr6＋黑色钝化的外观效果。