| 摘要 |
PROBLEM TO BE SOLVED: To provide a new chemical conversion treatment liquid with which a black chemical conversion coating having excellent corrosion resistance, decorativeness or the like can be deposited on the surface of an article made of zinc or a zinc alloy without using highly harmful components such as hexavalent chromium. SOLUTION: The composition for depositing a black chemical conversion coating consists of an aqueous solution of pH 1 to 5 satisfying the conditions in (1) to (3): (1) the condition where the heated reactant of the three components consisting of a trivalent chromium compound, carboxylic acids and the oxyacids of phosphorus is contained in an amount of 0.1 to 20 g/l as a chromium metal content; (2) the condition where a compound containing at least one kind of metal selected from the group consisting of nickel and cobalt is contained in an amount of 0.1 to 20 g/l as a metal content; and (3) the condition where nitric acid ions are contained in an amount of 0.01 to 10 g/l. COPYRIGHT: (C)2005,JPO&NCIPI
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