在连续热浸镀锌钝化液中以铈、钴元素替代铬元素(Cr6+),钝化液通过辊涂和烘干处理工艺得到钝化膜.试验通过电化学方法研究钝化膜的抗腐蚀行为.SEM照片表明所获得的钝化膜较Cr6+钝化膜具有更加致密的表面膜层,SiO2在膜层结构中阻碍了微裂纹的扩展,提高了膜层抗形变性能;极化曲线研究表明铈、钴抑制了阳极极化腐蚀过程,盐雾试验结果表明复合钝化膜较传统钝化膜具有更好的抗蚀性能.

Cerium salts,cobalt salts and silicon dioxide were used as chromate (Cr6+) replacers for continuous galvanizing steel sheets.The structure of passive films were observed by scanning electronic microscopy (SEM).The corrosion behavior of the films was evaluated with neutral salt spray test (NSS) and studied with electrochemical technique.The result of SEM showed that a perfect composite film was obtained on the steel sheet and SiO2 blocked the extension of microcracks and decreased the deformation range.The results of NSS and linear polarization showed that the corrosion resistance of the composite film was better than that of chromate (Cr6+) passivated film,cerium and cobalt salts could retard the anodic polarization of corrosion.