Study on coloring protective composite oxide film on aluminum surface

摘要

This work presents a preparation of composite aluminum anodizing oxide film and its coloring process. When a kind of ultra fine silicon particle with negative charge was doped into the micropores of film by electrochemical method, the obtained composite film has bulk density of 3.53 g·cm~(-3), cavity ratio of 10.6% and thickness of over 20 μm. Compared to traditional aluminum anodizing oxide films, the obtained new film gives higher hardness and mechanical properties. XRD analysis showed that silicon particles in composite oxide film were mainly composed of feldspar NaAlSi_3O_8. Furthermore, a kind of malonamide azo-colorant was introduced into the micropores of composite oxide film by in-situ synthesis to give various colors, where the malonyl group was as a bridge between aluminum oxide film and diazonium group. Properties evluation tests shows that the obtained colored decoration film exhibits high resistance to heat, salt-fog, mold and nature corrosion. Therefore, the composite aluminum anodizing oxide film is a promising candidate for application in stringent condition needing high protection as well as bright color.