ALUMINUM FOIL MATERIAL FOR ELECTRODE OF ELECTROLYTIC CAPACITOR

摘要

PROBLEM TO BE SOLVED: To provide an aluminum foil for an electrolytic capacitor, wherein formation of etch pits progresses uniformly and deeply into inner parts of aluminum to yield a high electrostatic capacitance at electrolytic etching by an alternating current without inducing excessive dissolving at the surface or inner parts. SOLUTION: The aluminum foil material for an electrode of the electrolytic capacitor has a composition comprising 30-450 ppm Fe and 30-300 ppm Si and having an Al purity of≥99.90% and is subjected to an AC etching treatment. Among intermetallic compounds present in the foil material, the ratio I(α-AlFeSi)/I(Al3Fe) in an X-ray diffraction pattern of an undissolved residue obtained by a thermal phenol method is 0.15-0.60, provided that I(α-AlFeSi) is the strength ofα-AlFeSi and I(Al3Fe) is the strength of Al3Fe. COPYRIGHT: (C)2009,JPO&INPIT