| 摘要 |
PURPOSE: To provide a method for manufacturing an aluminum foil in an electrode of an electrolytic capacitor, in which an electrostatic capacity can be increased, by forming an oxide film including a H2 O molecule on a surface of the aluminum foil. CONSTITUTION: In a manufacturing step for an aluminum foil used in an electrolytic capacitor, a solution of an additive of OH ions of 0.01 mol/l or below in water including an electrolyte with conductance of 10μS/cm or below is heated at a temperature from 75 deg.C to a boiling point. A pure aluminum foil with purity of 99.8wt.% or above is dipped in the solution at the temperature from 75 deg.C to a boiling point for 30 to 180 seconds to form an oxide film of 0.1 to 50g/m<2> on the pure aluminum foil. In addition to this way, the aluminum foil may be annealed at a temperature below 370$ deg.C after the dipping to form an oxide film of 0.1 to 150g/m<2> on the pure aluminum foil.
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