Taking ethyl orthosilicate, tetraethoxysilane, tetrabutyl titanate, aluminum nitrate and zinc acetate as precursor,and anhydrous acetic acid as catalyst, SiO_2-TiO_2-Al_2O_3-ZnO composite coating on the stainless steel surface was prepared by sol-gel method, and the coating was immersed in Na Cl solution. The corrosion morphology of the coating in Na Cl solution was observed by SEM. In order to determine the optimum sintering temperature of the composite coating, the differential thermal analysis(DTA) and t...