| 摘要 |
PROBLEM TO BE SOLVED: To obtain an aluminum foil for electrolytic capacitor, which has a high electrostatic capacity and also has a full bending strength, by a method wherein a pure aluminum material having a purity higher than a pacified purity is subjected to treatment with a hypochlarite-containing solution. SOLUTION: An aluminum foil having a purity of 99.98 wt.% and a thcikness of 90μm is dipped in a 1 wt.%-NaOH aqueous solution heated at 60 deg.C for 5 minutes to perform a degreasing treatment on the aluminum foil. After that, the foil is rinsed and after the foil is dipped in soda hypochlorite of a content of 7μ10<-2> mol/l and a caustic soda-containing aqueous solution of a content of 6×10<-3> mol/l, the foil is taken out from the aqueous solution and is subjected to annealing. After the annealing, an electrolytic etching is performed on the foil in a prescribed condition, and a formation treatment is performed on the foil on the conditions of ammonium adipate of a content of 100 g/l as a formation treating liquid, the temperature of the liquid of 85 deg.C, a current density of 20 mA/cm<2> and a formation voltage of 20 V to obtain an electrolytic capacitor.
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