Galvanizing is one of the important means of steel surface protection at home and abroad. Galvanized steel sheet is widely used in automobile manufacturing, household appliances, construction, aviation and other fields because of its good corrosion resistance. However, the zinc coating is easy to corrode in the air or wet environment, producing white corrosion products, affecting the appearance, and reducing the corrosion resistance. In order to slow down the corrosion rate of the zinc coating and prolong its service life, the surface of the zinc coating needs to be passivated to improve its corrosion resistance. Chromate passivation is widely used in metal passivation because of its simple process, low cost and good passivation effect. However, Cr6+is a highly toxic substance with carcinogenicity and serious harm to human body and the environment.

At present, countries around the world have begun to take measures to strictly limit the use of Cr6+, and the development of a new chromium free, environmentally friendly metal surface passivation process has received extensive attention. In recent years, organosilane coupling agent on metal surface is a new type of anti-corrosion treatment process. Because the process is pollution-free and the treated samples have good corrosion resistance, it has become a research hotspot of chromium free passivation on metal surface. The silane coupling agent passivation process is based on a silane reagent (general formula: X-R ′ - Si (OR ″) n, in which X represents the organic functional group R ′ and R ″ is alkyl) that can be hydrolyzed to produce silanol (Si OH). When the metal sample is immersed in the silane passivation solution, the surface of the base metal will form a dense organic silane film, which can play a good anti-corrosion effect. It is reported in the literature that the anti-corrosion effect of BTSE series silane on metals is equivalent to that of chromate. However, the preparation of its passivation solution is complex, and the repainting performance of the treated sample is not satisfactory, that is, the adhesion of the paint on the surface of the sample is poor, which seriously affects the subsequent processing and industrial application of the sample. The galvanized steel plate was passivated by vinyl trimethoxy silane coupling agent. The test results showed that the corrosion resistance of the sample passivated by silane coupling agent was greatly improved, the passivation film was dense, and the sample had good repainting performance.