ALUMINUM MATERIAL FOR ELECTROLYTIC CAPACITOR ELECTRODE, ITS MANUFACTURING METHOD AND ELECTROLYTIC CAPACITOR

摘要

PROBLEM TO BE SOLVED: To provide an aluminum material for electrolytic capacitor electrode which is capable of increasing and uniformizing the electrostatic capacity of an electrolytic capacitor under a high rated voltage. SOLUTION: The aluminum material having an oxide film on the surface of a substrate is constituted of aluminum whose Al purity is not less than 99.9wt.%, and which contains Si, Fe, Cu and Pb in the chemical composition thereof while (100) area ratio is not less than 90%. The solubilize time duration of the oxide film (TR) is 60-90 sec whose range of fluctuation is specified so as to be within 10 sec. Further, Pb and Cu are thickened in the surface layer of the oxide film so as to suffice formulae F1, F2 and F3 shown as ion strength ratio. Here; F1:7×103Pb(b)≤Pb(s)≤2.7×104Pb(b), F2:2.0Cu(b)≤Cu(s)≤8.0Cu(b), F3:1.5×10-2≤Cu(s)/Pb(s)≤6.0×10-2. In the formulae, Cu(b)and Pb(b)are concentration in the substrate while Cu(s)and Pb(s)are concentration in the surface layer of the oxide film. COPYRIGHT: (C)2005,JPO&NCIPI