| 摘要 |
PROBLEM TO BE SOLVED: To equalize the generation of a pit in the case of etching, to expand the effective surface area of an electrode foil, and to improve an electrostatic capacity. SOLUTION: In a manufacturing method for an etching foil for an electrolytic capacitor, an aluminum foil is passed between a pair of electrodes in an aqueous solution mixing at least one kind in phosphoric acid, nitric acid, sulfuric acid, and oxalic acid in a hydrochloric-acid aqueous solution; and an AC current is applied. In the manufacturing method for the etching foil for the electrolytic capacitor, a waveform for the positive half period of the AC current contains a section largely lowering from the case of a peak and the section rising or lowering constantly or slowly, from a time immediately after the completion of the lowering to the time of the completion of the half period. In the manufacturing method for the etching foil for the electrolytic capacitor, the ratio of a current value is 0.2 to 0.7 in the case of the completion of the lowering to the current value in the case of the peak, the ratio of the current value is 0.7 to 1.2 in the case of the completion of the subsequent half period to the current value immediately after the completion of the lowering, the ratio of the time is 0.1 to 0.7 from the case of the start of the half period to the case of the peak to a half-period time, and the ratio of the time is≤0.4 from the time of the peak to the time of the completion of the lowering to the half-period time. COPYRIGHT: (C)2007,JPO&INPIT
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