| abstract |
Invention provides a zinc immersion coating solution used in the double-zincate method for applying first and second zinc immersion coating treatments to aluminum or aluminum alloy. Zinc immersion coating solution used for first zinc immersion coating treatment at least contains a zinc compound, alkali hydroxide, iron salt, chelating agent for complexation of iron ions, and zinc immersion coating inhibitor that is at least one out of the group consisting of a polymer of a secondary amine, polymer of a tertiary amine, and polymer of a quaternary amine, or copolymer containing the same, and zinc immersion coating solution used for second zinc immersion coating treatment at least contains a zinc compound, alkali hydroxide, iron salt, chelating agent for complexation of iron ions, and zinc immersion coating inhibitor that is at least one out of the group consisting of a primary and secondary amines, and a tertiary amine. |