Electrolytic Coloring of Aluminum in Ferrous Sulfate Solution

摘要

Aluminum or its alloys are anodized in solutions such as sulfuric acid, phosphoric acid, chromic acid, oxalic acid, et al. by direct current. An anodic oxidation film results with lots of pores. When the film is treated in the solution containing metal ions by alternating current the metal ions are reduced and deposit on the bottom of the pores and absorb and diffuse incident light to make the film colored. The primary solutions for electrolytic coloring are nickel sulfate, stannous sulfate solution, cobaltous sulfate solution, et al. or their mixtures. Ferrous sulfate is low in price and has good prospects for use in electrolytic coloring.