热浸镀锌层偏钒酸盐转化膜成膜工艺的研究

Study on Process of Metavanadate Conversion Coating on Hot-dipped Galvanizing Coating

为了获得可提高热浸镀锌层耐蚀性能、对环境污染小的转化膜工艺,采用无毒偏钒酸盐对热浸镀锌层进行钝化,研究了转化液组成、pH值、钝化处理温度及时间对钝化成膜及膜层耐蚀性的影响,确定了最佳工艺:NaVO35 g/L,pH值为1.3,处理温度为室温(25～30℃),处理时间10～30 min。通过中性盐雾(NSS)试验、附着力测试和电化学极化测试考察膜层的性能,结果表明,采用该工艺可获得耐蚀性明显高于纯锌层的优良转化膜,且其附着力好,结合牢固。

In order to improve the corrosion resistance of the hot-dipped galvanizing coating,reduce the pollution to the environment,the non-toxic passivition process by metavanadate for hot-dipped galvanizing coating was investigated.Effects of bath composition,pH,treatment temperature and time on the properties of passivition film were discussed.The results show that the optimum process parameters range for the metavanadate conversion coating are NaVO3 5 g/L,pH 1.3,25～30 ℃,10～30 min.The results of neutral salt spray（NSS） test,adhesion test and electrochemical polarization test show that the coating with better corrosion resistance and good adhesion is obtained by the optimum process.