ALUMINUM FOIL FOR ELECTROLYTIC CAPACITOR AND METHOD OF MANUFACTURING THIN SHEET FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an aluminum foil for electrolytic capacitor in which the number of elements to be controlled is reduced and high capacitance is attained, and a method of manufacturing a thin sheet for the same. SOLUTION: The aluminum hard foil for electrolytic capacitor contains 5-20 ppm Cu, 1-6 ppm V+Cr+Ni+Zr, 0.05-1.5 ppm Ni+Zr by mass and the balance aluminum with inevitable impurities, Al content is >=99.98% of the foil by mass, the maximum diameter of an intermetallic compound containing Fe is <=20 nm and Si element and an intermetallic compound containing Si are substantially not detected in the observation by 230,000 magnification. The method of manufacturing the thin sheet for hard foil is performed by heating and keeping slab having the said composition at 530-570 deg.C for >=3 hours to homogenize and hot-rolling through a plurality of passes to form a fire rolled sheet of >=385 deg.C into a fire rolled sheet of 275-320 deg.C at a pass F2 direct before a final pass F1 and to form into a fire rolled sheet of <=230 deg.C at the final pass F1 in the final pass F1 and the pass F2 of one pass direct before the final pass and cold rolling.