ALUMINUM FOIL FOR ELECTROLYTIC CAPACITOR

摘要

PROBLEM TO BE SOLVED: To prevent an Al foil of at least a specified purity from being folded by specifying the distribution density of pores over specified size. in the foil to be heated after etching. SOLUTION: A slab having an Al purity of 99.97% or more is cast by the DC casting. After grinding the surface of the slab by specified depth, it is homogenized, immediately hot rolled and cold rolled to form a hard foil. The foil is heat treated in an inert gas into a soft foil which is then treated to form an Al foil having a porous surface density of 150 pores/mm<2> or less of pores of 0.5μm or less before etching. This ensures an adequate strength of the core and prevents the foil from folding.