Abstract: Electrode foil includes an aluminum alloy having a composition in a region at least 10 ?m deep from a surface of the foil. The composition includes aluminum as a main component and zirconium of at least 0.03 at % and at most 0.5 at %.

Abstract: The present invention provides a method of manufacturing anode foil for aluminum electrolytic capacitors with high capacitance and decreased leakage current. The method has the following steps: dipping etched aluminum foil into pure water having a temperature of 90° C. or higher so as to form a hydrated film on the foil; attaching organic acid to the surface of the hydrated film; performing main chemical conversion on the aluminum foil with application of formation voltage after the attaching step; performing depolarization on the aluminum foil after the main chemical conversion step; and performing follow-up chemical conversion on the aluminum foil after the main chemical conversion step. The main chemical conversion treatment has two-or-more stages. In the first stage of the treatment, the foil is dipped into a phosphate aqueous solution, and in the last stage, it is dipped into an aqueous solution different from the phosphate aqueous solution.

Abstract: A method of manufacturing a positive electrode foil of an aluminum electrolytic capacitor is provided in which anodizing conditions are optimally determined and automatically set to minimize the loss of production and to produce a constant quality of the positive electrode foil. The method comprises an etching process and an anodizing process. An etched foil produced in the etching process is subjected to a constant current inspection, and then, the anodizing conditions are determined from the result of the constant current inspection. The anodizing conditions are transferred to a control panel in the anodizing process where they are automatically registered as its settings. Also, an apparatus for manufacturing the positive electrode foil is provided which has a voltage sensor connected between an output running roller and cathode electrodes in an anodizing tank. A voltage measured by the voltage sensor is fed back to a direct-current source for controlling its output voltage.

Abstract: A method of manufacturing electrode foil for aluminum electrolytic capacitors and an AC power supply unit used therewith are disclosed. An etching is performed on an aluminum foil immersed in an electrolytic solution by applying an AC current to a pair of electrodes in the electrolytic solution. A waveform of the AC current is a deformed sine wave including a period of time (a) when an electric current rises from zero to a peak value, and another period of time (b) when the electric current falls from the peak value to zero. With the periods of time (a) and (b) made different from each other, the surface area of the aluminum foil is efficiently expanded by the etching and an enhancement of electric capacity of the electrode foil is obtained.

Abstract: A method of manufacturing electrode foil for aluminum electrolytic capacitors and an AC power supply unit used therewith. An etching is performed on an aluminum foil immersed in a electrolytic solution by applying an AC current to a pair of electrodes in the electrolytic solution. A waveform of the AC current is a deformed sine wave including a period of time (a) when an electric current rises from zero to a peak value, and another period of time (b) when the electric current falls from the peak value to zero. With the periods of time (a) and (b) made different from each other, the surface area of the aluminum foil is expanded by the etching efficiently and an enhancement of electric capacity of the electrode foil is obtained.

Abstract: A method of manufacturing a positive electrode foil of an aluminum electrolytic capacitor is provided in which anodizing conditions are optimally determined and automatically set to minimize the loss of production and to produce a constant quality of the positive electrode foil. The method comprises an etching process and an anodizing process. An etched foil produced in the etching process is subjected to a constant current inspection, and then, the anodizing conditions are determined from the result of the constant current inspection. The anodizing conditions are transferred to a control panel in the anodizing process where they are automatically registered as its settings. Also, an apparatus for manufacturing the positive electrode foil is provided which has a voltage sensor connected between an output running roller and cathode electrodes in an anodizing tank. A voltage measured by the voltage sensor is fed back to a direct-current source for controlling its output voltage.

Abstract: This invention includes a first step for dipping etched aluminium foil into pure water of high temperature for a predetermined period of time, a second step for dipping the aluminium foil into an aqueous solution containing an organic acid and at least one kind of a salt thereof after the first step, and a third step for subjecting the aluminium foil to a forming treatment in an electrolytic solution after the second step, wherein either straight saturated dicarboxylic acid having an odd number of carbons or trans-straight unsaturated dicarboxylic acid is used or organic acid having an aromatic ring and a carboxyl group is used as the organic acid in the second step, whereby leakage current characteristics are improved by weakening a dissolving action to a hydrated film and strengthening a bonding action to the hydrated film.