目的 阻碍热镀锌板出现白锈，提高镀锌层的耐腐蚀性能。方法 采用正交试验法优化出添加虫胶水溶液的有机无机复合钝化液。通过电化学Tafel极化曲线、交流阻抗（EIS）、乙酸铅点滴和中性盐雾试验，对比分析基体、硅酸盐+虫胶复合钝化膜与铬酸盐钝化膜的耐腐蚀性能。采用摩擦法测试对比分析基体和无铬钝化膜试样的附着性能，并通过扫描电子显微镜、X射线光电子能谱和红外光谱对形貌和结构进行分析。结果 添加虫胶水溶液的复合钝化膜表面平整致密，72 h中性盐雾试验后的腐蚀面积小于10%。乙酸铅点滴试验和电化学测试显示，复合钝化膜的耐腐蚀性能较基体好。附着力试验测试显示，复合钝化膜具有良好的附着能力。 结论 因为复合钝化液中的虫胶与硅酸盐交织为O—Si—CH2结构，与金属离子结合生成致密的膜层附着在镀锌层表面，使得复合钝化膜致密平整，且使腐蚀过程得到了强烈的抑制。

The paper aims to hinder the appearance of white rust on the hot-dip galvanized sheet and improve corrosion resistance of galvanized sheet. An organic-inorganic composite passivation film with an aqueous solution of shellac was prepared by orthogonal test. Tafel polarization curve measurement, AC impedance spectroscopy (EIS), lead acetate dripping corrosion test and neutral salt spray test were used to compare and analyze the corrosion resistance of the galvanized layer and chromate passivation plating of matrix, silicate + shellac composite passivation. The adhesion properties of the substrate and the chromium-free passivation sample were tested by the friction method. The morphology and structure were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. The results showed that the surface of the composite passivation film with added aqueous solution of shellac was flat and dense; and the corroded area was less than 10% for the composite film after 72-h NSS test. The lead acetate test and electrochemical test showed that the corrosion resistance of the composite passivation film was better than that of the substrate. The adhesion test showed that the composite passivation film had good adhesion. It can be seen from the test results that the shellac and silicate in the composite passivation solution are interwoven into O—Si—CH2 structure, and a dense film layer is formed on the surface of the galvanized layer by bonding with metal ions, making the composite passivation film dense and flat. And the corrosion process is strongly suppressed.