| 摘要 |
PURPOSE:To electrolytically-color Al material surely in a blueish gray series, by chemically forming a film treated with phosphoric acid on the surface of the Al material and thereafter forming an anodic oxidation film in a sulfuric acid bath and then performing electrolysis in an electrolytic coloring bath contg. coloring components. CONSTITUTION:A material is subjected to immersion treatment or electrolytic treatment in a bath contg. phosphate ions. As this bath, a phosphoric acid aq. soln., a mixed aq. soln. of it and sulfuric acid or alkali, a phosphate aq. soln. and a mixed aq. soln. of this and sulfuric acid are used. A film treated with phosphoric acid is chemically formed on the surface of the Al material by the above-mentioned treatment. Then an anodic oxidation film is formed on the Al material having the chemical conversion film in a sulfuric acid bath. Thereafter this Al material is subjected to electrolytic treatment with AC, DC or superimposed current of AC and DC in an electrolytic coloring bath. This electrolytic coloring bath contains nickel salt and zinc salt or nickel salt and zinc salt and molybdate as a coloring component and nickel ion as a masking material and a supporting electrolyte and is used after regulating pH to >=4.5. Thereby coloring to black from a gray series can be performed on the surface of the Al material.
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