| abstract |
(57) [Summary] (With correction) [Problem] While a passivating film with better corrosion resistance is formed on the surface of stainless steel in a single process operation, not to mention rust, oil and other dirt Various oxide scales are removed at the same time. SOLUTION: 0.5% by weight or more of sulfuric acid, phosphoric acid, citric acid, tartaric acid, oxalic acid, malic acid, succinic acid, gluconic acid, Based on one or two or more of sodium, potassium and ammonium salts of acids such as glycolic acid, succinic acid and the like that act non-oxidatively on stainless steel, and further 0.01% by weight or more, preferably 0 0.05% by weight or more of hydrofluoric acid or an aqueous solution containing one or more of its sodium, potassium, and ammonium salts as a passivation accelerator is used as an electrolyte, and the surface of the treated stainless steel and the counter electrode AC electrolytic treatment is carried out with a water-absorptive substance made of natural or synthetic fiber interposed between them as a diaphragm. |