Process for preparing an electrode foil for use in aluminum electrolytic capacitors

摘要

A process for preparing an electrode foil for use in aluminum electrolytic capacitors is disclosed which comprises the steps of: subjecting an aluminum base foil to a first anodic treatment in an aqueous solution of oxalic acid or sulfuric acid; subjecting the base foil so treated to a second anodic treatment in an aqueous solution of boric acid or adipic acid; and immersing the base foil so treated into an aqueous solution containing phosphoric acid or a salt thereof. Also disclosed is an electrode foil prepared by this process, which comprises an aluminum base foil, an anodic oxide film disposed on the base foil, and a porous oxide film disposed on the anodic oxide film, wherein phosphate ions are adsorbed on the surface of the porous oxide film.