| 摘要 |
PROBLEM TO BE SOLVED: To obtain an electrolytic capacitor having a large capacitance per unit area. SOLUTION: An aluminum alloy contains 1 to 100 ppm Si, 1 to 100 ppm Fe, 1 to 100 ppm Cu, 1 to 30 ppm Ga, 0.01 to 0.5 ppm Ni, 0.01 to 0.5 ppm Co, 0.01 to 0.05 ppm Mo, and the balance Al with inevitable impurities and, when required, 0.01 to 10 ppm Na and one or more of 0.01 to 1 ppm In, 0.01 to 1 ppm Sn, 0.001 to 0.2 ppm Pb and meets 0.05<=Ga/[Cu+100×(Ni+Co+Mo)]<=1 (1) (containing no Na) or 0.05<=(Ga+Na)/[Cu+100×(Ni+Co+Mo)]×1 (2) (containing Na). Therefore, a high surface roughening rate is obtained, because pits are densely formed in a uniformly distributed state when the surface of the alloy is roughened, and, as a result, a capacitor having a high capacitance can be obtained.
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