Abstract
Behavior of halogen ions to anodized aluminum films was investigated when the films were dipped in sodium halide solutions. The following results were obtained: (1) The decreasing order of adsorption of halogen ions on the anodized film in H2SO4 was arranged as F′>Cl′>Br′. The amount of adsorbed F′ increased with the increase in concentration and film thickness and rise of temperature; also increased on more acidic side. (2) The amount of adsorbed F′ on the anodized film in H2SO4 decreased by treatment with boiling water. (3) The decreasing order of adsorption amount of F′ on various anodized films was arranged as in H2SO4> in (COOH)2> in Na3PO4> in NH4F-NH4OH solution. (4) The decreasing order of the amount of passed halogen ions through a thin anodized film (formed by thin aluminum foil) was arranged as Cl′>F′>Br′. The amount of passed F′ decreased on more acidic side. The film prepared in NH4F-NH4OH solution had greater passability than that in H2SO4. In the next stage, the sealing effects of metallic halides were investigated and the following results were obtained: (A) The best results were obtained by addition of chromium or nickel fluoride to the film prepared in H2SO4. (B) The sealing effects of metallic halides had a similar tendency to the adsorption of halogen ions. (C) The suitable conditions for sealing treatment were about 0.02mol of concentration of solution, about 50°C of temperature of treating solution, and about 10min. of dipping time.
