| 摘要 |
PROBLEM TO BE SOLVED: To obtain a steel excellent in corrosion resistance and usable in a coated or uncoated state with high reproducibility by coating the surface of steel with rust contg. a specified amt. of one or more kinds among Ti, Nb, Ta, Zr, V and Hf. SOLUTION: In a steel surface or a steel rust layer, one or more kinds among Ti, Nb, Ta, Zr, V and Hf are incorporated by >=0.01 wt.%, preferably >=0.05% in total. In these elements, Ti is preferably used as the essential one in particular. In this way, a stable rust layer in which the amorphous substance of rust generated while using the steel andα-FeOOH are suppressed can be formed. As a result, high corrosion resistance can be exhibited in a salt corrosive environment. As the rust generated while using the steel is dense, the effect of suppressing the intrusion of corrosive factors such as chloride ions is higher. This treatment is executed, e.g. by cleaning the steel surface and thereafter applying an aq.soln. contg. Ti, Nb, Ta, Zr, V and Hf thereto.
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