| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum foil for electrolytic capacitors capable of providing such capacitor as excellent in electrostatic capacitance per unit area by improving a roughening rate. SOLUTION: The aluminum foil 1 for electrolytic capacitors is used for etching process in which the ratio D (D=barrier film thickness/total film thickness) between film thickness of a barrier film 2a of a surface oxide coat 2 and a total film thickness satisfies 0.25≤D≤0.45. A preferred composition contains Si: 5-50 ppm, Fe: 5-50 ppm, Cu: 10-100 ppm, Pb: 0.1-5 ppm, and Na: 0.1-10 ppm, with a remaining part consisting of Al and inevitable impurities. In the inevitable impurities, Mn, Zn, and Ga are 10 ppm or less, respectively, being 20 ppm or less in total, with a content of Zr being 5 ppm or less. An etching pit is formed constant in high density, resulting in providing a good roughening rate. COPYRIGHT: (C)2007,JPO&INPIT
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