| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface treatment method for aluminum or an aluminum alloy by which stable degreasing treatment can be performed in a rising period after initial make-up of an electrolytic bath. SOLUTION: An aluminum can is treated by the following stages including degreasing treatment: prerinsing-prewashing-washing (degreasing treatment)- primary rinsing-treatment (chemical conversion film treatment)-secondary rensing-deionized water rinsing-drying. In the degreasing treatment stage, on initial make-up of an electrolytic bath, aluminum salt is added to an acid bath so that the concentration of aluminum ions is controlled to the prescribed one, and, even in the rising period, the level of the aluminum ion concentration of the stable bath is held.
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