| 摘要 |
PROBLEM TO BE SOLVED: To obtain a surface treated steel excellent in corrosion resistance by irradiating light to the coating having a two layer structure in which, after formation of an oxide coating layer contg. zinc oxide as a lower layer on the surface of a steel, coating contg. titanium oxide is formed as an upper layer with light. SOLUTION: This surface treated steel is the one in which the surface of a steel is applied with a primary coating layer contg. zinc oxide by 12 to 100wt.% in the solid content in the coating as a lower layer, and it surface is applied with a secondary coating layer contg. 15 to 100wt.% titanium oxide. This coating having a two layer structure is irradiated with light. In the case the content of zinc oxide in the lower layer coating is less than 12%, the effect of improving its corrosion resistance is low. As for the method for forming the lower layer coating, there is no limitation in particular, and, e.g. zinc oxide may be adhered thereto by an electrolytic method or the galvanized steel may be subjected to oxidizing treatment or electrolytic treatment. In the case the content of titanium oxide in the secondary coating layer is less than the lower limit, the effect of improving its anticorrosive properties is low. As for the method for forming the secondary coating, there is no prescription, and, e.g. a PVD method, a CVD method or the like may be adopted.
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