Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solu-tions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminumfoils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various elec-trochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate byglutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field.In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfullyformed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperatureof the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the alu-minum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acidanodizing due to the relatively low dissociation constants associated with the acid. Acid dissociationconstants are an important factor for the fabrication of anodic porous alumina films