Method for preparing anode electrode for high voltage electrolytic capacitor

Abstract

Disclosed is a method for forming an aluminum oxide film of a large surface area on an electrode for a high voltage electrolytic capacitor. In accordance with the method, an oxide film of a uniform thickness is formed, prior to a process of etching the oxide film. A re-anodization is then partially conducted for an etched portion of the oxide film. The resultant oxide film has an increased surface area. The method of the invention makes it possible to prepare a dielectric oxide film having characteristics of a uniform thickness and a large surface area. In accordance with the invention, it is possible to expect an increase in the capacitance of electrolytic capacitors.