Post-treatment method to improve the quality of oxide film of medium and high pressure electrode foil

摘要

The present invention discloses a post-treatment method for improving the quality of the oxide film of the medium-high pressure electrode foil. One or more phosphates are used as the treatment liquid in the post-treatment tank, a negative electrode is provided in the treatment tank, and an electric field is applied to the chemical conversion foil by controlling a current with a variable current density to form an oxide film. The effect of post-treatment can be improved, a current with variable current density is applied to accelerate the ionization of the treatment liquid, and phosphate ions permeate the oxide film of the chemical conversion foil to penetrate internal defects and oxygen on the surface. Leakage current can be reduced by forming the adsorption of ions and rapidly generating Al ^3+, which is a defect of the oxide film, on the oxide film. Phosphate ion can react with aluminum on the surface of the oxide film to form an aluminum phosphate layer, and can prevent the hydration reaction between external water and the chemical foil. By reducing the current density, it is possible to prevent deterioration of the quality of the oxide film due to overproduction of aluminum phosphate, reduce the leakage current of the chemical foil oxide film, improve the hydration resistance performance, and improve the quality of the oxide film. , The life of the aluminum electrolytic capacitor can be improved.