Electrolytic foil having a tunnel-like pits of uniform depth, an electrolytic capacitor and manufacturing method of the foil to the electrode as it

摘要

PROBLEM TO BE SOLVED: To produce an electrolytic foil free from piercing tunnel-shaped pits reducing mechanical strength and increased in capacitance as possible, to provide a method for producing the same and to provide an electrolytic capacitor using the foil as electrode foil. ;SOLUTION: As to aluminum foil of 70 to 150 μm foil thickness, d.c. electrolysis is started at the maximum current density of ≥1500 mA/cm2 initial current density in an aq. soln. of hydrochloric acid, sulfuric acid, or the like, thereafter, it is rapidly reduced to ≤100 mA/cm2, and the electrolysis is finished in a short time of 10 to 30 sec, by which electrolytic foil for an electrolytic capacitor having tunnel-shaped pits of uniform depth on both surfaces of the aluminum foil and having a nonpiercing layer of 10 to 30% foil thickness on the center part is formed.;COPYRIGHT: (C)2000,JPO