Process for improving an anodizing film, an anodizing film structure and an aluminum-alloy-made outboard engine

摘要

A process for forming an improved anodizing film on the surface of an aluminum alloy material. The film is impregnated with an amorphous substance which fills pores formed in the film during its growth. If the film has a flaw reaching the aluminum alloy material, the amorphous substance and aluminum form a layer of passivity which restrains the corrosion of the aluminum alloy material.