Chemical conversion solution for aluminum or aluminum alloy, chemical conversion method, and chemical conversion film

Abstract

The present invention addresses the problem of providing a chemical conversion surface treatment solution capable of forming a chemical conversion film with excellent corrosion resistance and design on an article, in which the surface portion comprises aluminum or an aluminum alloy, using a process similar to conventional chemical conversion without using components that have high environmental impact such as hexavalent chromium, trivalent chromium, or fluorine. The present invention relates to a chemical conversion solution for aluminum or aluminum alloy comprising an aqueous alkaline solution that contains a permanganic acid compound and at least one kind of metal oxygen acid compound selected from a group consisting of vanadic acid compounds, molybdic acid compounds, tungstic acid compounds, zirconic acid compounds and niobic acid compounds.

Description

technical field

[0001] The present invention relates to a chemical conversion treatment liquid for aluminum or aluminum alloy, a chemical conversion treatment method and a chemical conversion film. Background technique

[0002] Aluminum-based metal materials (particularly low-corrosion-resistant alloy-based aluminum containing a large amount of copper such as A2024) are chemically treated to form a metal compound film on their surface in order to improve their corrosion resistance or rust resistance.

[0003] Typical chemical conversion treatments include hexavalent chromium chemical conversion treatment and trivalent chromium chemical conversion treatment. The film obtained by the hexavalent chromium conversion treatment has a golden color tone and is also excellent in designability. However, the hexavalent chromium conversion treatment liquid contains components that damage the environment, such as hexavalent chromium and fluorine, and imposes a large load on the environm...

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