Alkali assisted water treatment of aluminum promoting the growth of hydrated oxide film for energy conservation

Aluminum anodizing process consumes a lot of energy for ions migration in solid phase. Commonly, the aluminum foil is treated by boiling water to form crystalline γ'-Al2O3 for reducing the energy consumption. In order to improve water treatment, the alkaline buffer solution was used for promoting the growth of hydrated oxide film and contributed to formation of crystalline alumina. As a result, the obtained samples consumed 12.08% less energy during anodizing process compared with that of water treated samples. The hydrated oxide film was detected by means of morphological and electrochemical analysis, which indicated the alkaline treatment promoted generation of hydrated oxide film as well as formed dense anodic oxide film after anodizing. Furthermore, the pretreated samples owned denser anodic oxide film verified by X-ray diffraction and electrochemical analysis, which implied less production of alumina on the same electrical performance. Therefore, the alkaline solution treatment of aluminum/hydrated oxide film has a good prospect for getting rid of the limitation of high energy consumption in electrolytic capacitors industry.