Abstract: Sub pits are suppressed from branching in a surface layer of an aluminum foil, and an electrode foil for an aluminum electrolytic capacitor with a large electrostatic capacitance and a method of manufacturing the same are provided. A large number of main pits are formed by etching on both surfaces of the aluminum foil to extend from the surfaces in a thickness direction of the foil, sub pits are formed to branch away from the main pits for a range from a vicinity of a surface layer portion of each main pits excluding the surface layer portion, to inner ends of the main pits. Since the sub pits are not formed in the surface layer of the aluminum foil, the sub pits can be increased in density effectively to the electrostatic capacitance, allowing the electrode foil for the aluminum electrolytic capacitor to have high mechanical strength and high electrostatic capacitance.

Abstract: Sub pits are suppressed from branching in a surface layer of an aluminum foil, and an electrode foil for an aluminum electrolytic capacitor with a large electrostatic capacitance and a method of manufacturing the same are provided. A large number of main pits are formed by etching on both surfaces of the aluminum foil to extend from the surfaces in a thickness direction of the foil, sub pits are formed to branch away from the main pits for a range from a vicinity of a surface layer portion of each main pits excluding the surface layer portion, to inner ends of the main pits. Since the sub pits are not formed in the surface layer of the aluminum foil, the sub pits can be increased in density effectively to the electrostatic capacitance, allowing the electrode foil for the aluminum electrolytic capacitor to have high mechanical strength and high electrostatic capacitance.

Abstract: Sub pits are suppressed from branching in a surface layer of an aluminum foil, and an electrode foil for an aluminum electrolytic capacitor with a large electrostatic capacitance and a method of manufacturing the same are provided. A large number of main pits are formed by etching on both surfaces of the aluminum foil to extend from the surfaces in a thickness direction of the foil, sub pits are formed to branch away from the main pits for a range from a vicinity of a surface layer portion of each main pits excluding the surface layer portion, to inner ends of the main pits. Since the sub pits are not formed in the surface layer of the aluminum foil, the sub pits can be increased in density effectively to the electrostatic capacitance, allowing the electrode foil for the aluminum electrolytic capacitor to have high mechanical strength and high electrostatic capacitance.

Abstract: There is provided a method of producing an electrode foil for use in aluminum electrolytic capacitors. This method includes the steps of (a) introducing a predetermined length of an aluminum foil into an electrolytic solution without supplying any current; (b) supplying a current to the aluminum foil until voltage becomes constant while keeping the aluminum foil stationary therein; (c) repeating the steps (a) and (b) for another predetermined length of the aluminum foil; and (d) finally holding the aluminum foil thus obtained while applying a constant voltage thereto. According to this method, an excellent electrode foil can be obtained which provides an aluminum electrolytic capacitor with high capacitance and significantly reduced leakage current.

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 is an electrolytic capacitor comprising a titanium-deposited aluminum foil used as the cathode. An aluminum foil is subjected to vacuum deposition of titanium with a deposition angle, thereby obtaining an electrolytic capacitor having a larger electrostatic capacitance than the conventional.

Abstract: A method for electrolytically etching an aluminium foil for use as an electrode of an aluminium electrolytic capacitor is described. In the method, an aluminium foil is electrolytically etched an on the surfaces thereof in a 3 to 25% hydrochloric acid solution containing aluminium chloride by application of an AC current. The AC current has a waveform, each cycle of which consists of positive and negative half cycles and an OFF time interval between the respective half cycles at which the AC current becomes zero whereby the size of pits formed by the etching is suitably controlled.

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.

Abstract: Optimum conditions, employed in an etching process of an aluminum foil for use in an electrolytic capacitor, are selected and combined together for realizing an extension of the effective surface area of the foil. This extension also gives an enlargement of the electrostatic capacitance of the foil electrode as well as an enhancement of the mechanical strength of the foil itself, the latter had been considered to be hardly compatible with the former.

Abstract: Optimum conditions, employed in an etching process of an aluminum foil for use in an electrolytic capacitor, are selected and combined together for realizing an extension of the effective surface area of the foil. This extension also gives an enlargement of the electrostatic capacitance of the foil electrode as well as an enhancement of the mechanical strength of the foil itself, the latter had been considered to be hardly compatible with the former.