| 摘要 |
PURPOSE: To prevent corrosion of a steel material, which is used in contact with soil at ground surface and air-bearing soil layer. CONSTITUTION: A steel material is covered with a film made of a metal, which is potentially baser than the steel material, by the thickness of 40-500μm. The film has a film controlling layer, in which the ratio 100×POx /PMe (%) of the main component peak value POx of the metal oxide measured by X-ray diffraction to the main component peak value PMe is 0.1-5 and the thickness of which is 40μm or more. As the metal, Zn, a Zn-Al alloy or Al is effective. The film is produced by spray-coating the metal. Thus, the durable years of the steel material used in contact with soil at ground surface and air-beating soil layer can be improved remarkably. Its long term durability can be obtained more simply and at a lower cost then ever.
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