| 摘要 |
PROBLEM TO BE SOLVED: To provide a hexavalent chrome-free chemical conversion treatment liquid capable of providing the corrosion resistance and the coating film adhesiveness equivalent to or more than those of a hexavalent chromate film without performing any pickling before the chemical conversion, and a chemical conversion treatment method by the same. SOLUTION: The chemical conversion treatment liquid contains a trivalent chromium compound, a zirconium compound and a dicarboxylic acid, contains 10-2,000 mg/liter as Cr of at least one of CrF<SB>3</SB>3H<SB>2</SB>O, Cr(NO<SB>3</SB>)<SB>3</SB>9H<SB>2</SB>O as the trivalent chromium compound, contains 10-2,000 mg/liter as Zr of at least one of (NH<SB>4</SB>)<SB>2</SB>ZrF<SB>6</SB>, H<SB>2</SB>ZrF<SB>6</SB>, K<SB>2</SB>ZrF<SB>6</SB>, Na<SB>2</SB>ZrF<SB>6</SB>as the zirconium compound, and contains 0.1-1,000 mg/liter of at least one of di-carboxylic acid which is expressed by R<SB>1</SB>-(COOH)<SB>2</SB>[R<SB>1</SB>=C<SB>2</SB>to C<SB>5</SB>]. In the method, a base material of an aluminum alloy is treated at the treatment temperature of 30-60°C, for the treatment time of 10 seconds to 10 minutes in a pH range of 1.5-6.0 by using the chemical conversion treatment liquid without any pre-treatment with acid. COPYRIGHT: (C)2007,JPO&INPIT
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