To prevent a steel material from being corroded and reduces the frequency of painting by forming a coating film layer of a specific alkyl silicate hydrolytic condensate on the air-exposed surfaces or the like of steel materials and allowing an anticorrosive electric current to flow.
Hydrophilic and slightly water-soluble film layers 2, 3 that contain an alkyl silicate hydrolytic condensate represented by the formula: R1nSi(OR2)4-n (R1 is a 1-8C organic group; R2 is a 1-5C alkyl, n is 0 or 1) are formed on steel material 1 having the surfaces exposed to the air or a coated steel material 1 and an anticorrosive electric current is allowed to flow according to the impressed current protection technique using an external energizer whereby the steel material 1 is prevented from being corroded. In an preferred embodiment, an anode 4 that is slightly soluble in water and is made of an electroconductive material is laminated on the coating film layers 2, 3, while the steel material 1 is used as a cathode, and a direct current is applied between the anode 4 and the cathode 1 to flow the anticorrosive current to inhibit the steel material from being corroded.
TAKI TORU
NAGAI YOSHINORI
MATSUMOTO GOJI
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