アルミニウム陽極酸化皮膜の青色電解着色

抄録

The AC electrolytic blue coloring of anodic oxide films on aluminum was studied in aluminum sulfate solutions containing nickel (II) sulfate, cobalt (II) sulfate or zinc sulfate. Electrolytes containing zinc sulfate yielded light grayish films, while those containing nickel (II) sulfate or cobalt (II) sulfate yielded gray, grayish blue, or blue colored films at voltages higher than 26V AC. Anodic stripping was conducted to clarify the mechanism of such color changes. The results suggested that Ni²⁺ and Co²⁺ were first reduced and deposited in the film pores and that the deposits were than hydroxidized and oxidized by OH^- produced by the electrolysis of the water. It is also concluded that the aluminum hydrate and oxide on the upper sides of the films were formed simultaneously by migration and deposition of multinuclear complex ions of Al³⁺.