Abstract: An electrolytic capacitor having a capacitor element which includes a plurality of foils, and having also an electrolyte, wherein the plurality of foils and the electrolyte are contained in a cylindrical case having on one of its end surfaces a pair of lead terminals to connect to the capacitor element and on another of its end surfaces an explosion preventive vent is electrically aged. The electrolytic capacitor is placed onto a support table so that the capacitor's end surface having the lead terminals is not below the capacitor's end surface having the explosion preventive vent. Each one of the pair of lead terminals is connected to a respective one of a pair of electrode sections. An electric voltage is then applied across the pair of lead terminals through the pair of electrode sections.

Abstract: 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.

Abstract: In the method for making electrode foil for an aluminum electrolyte capacitor, in order to obtain a formation layer of aluminum foil having superior waterproof nature and good stability, surface-roughened aluminum foil has hydration treatment, first formation treatment, dipping in aqueous solution of ammonium dihydrogen phosphate and second formation.

Abstract: The present invention relates, in an aluminum electrolytic capacitor using aluminum foil as its electrode, to a method for producing safely an anode foil having a high surface-area-enlarging factor at a low cost, by adding anions, which have oxide film-forming action over aluminum surface, to aqueous solution containing chloric ions, and in this solution taking the aluminum foil as an anode, a pulse current is applied between this and a counter electrode, thus while forming an oxide film over the surface, the aluminum foil is etched at the same time, and thereby the positive electrode foil having a high surface-area-enlarging factor is obtainable.