| 摘要 |
PROBLEM TO BE SOLVED: To obtain a capacitor having excellent electrolytic capacitance per unit area by effectively increasing a roughening ratio in an electrolytic etching process. SOLUTION: An aluminum material having a composition containing, by mass, 5 to 100 ppm Si, 5 to 100 ppm Fe, 10 to 100 ppm Cu, 0.1 to 5 ppm Pb and 1 to 50 ppm rare earth elements, and the balance Al with inevitable impurities is cold-rolled in such a manner that the final cold rolling ratio is controlled to 15 to 25%, and is subjected to final annealing at 530 to 600°C for 4 to 10 hr, In this way, aluminum foil in which the relation between the concentration peak depth (P1) of Pb and the concentration peak depth (P2) of rare earth elements from the surface satisfies P1>P2 can be obtained. The uniform treatment is performed in pretreatment to etching, and pits are uniformly formed to a high density at the time of etching, so as to obtain a high roughening ratio. COPYRIGHT: (C)2006,JPO&NCIPI
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