ETCHING FOIL FOR ALUMINUM ELECTROLYTIC CAPACITOR AND CHEMICAL CONVERSION FOIL THEREOF

摘要

PROBLEM TO BE SOLVED: To provide an etching foil for aluminum electrolytic capacitors in which the pit density is improved and the pit length is uniformized, and to provide a chemical conversion foil for aluminum electrolytic capacitors which is obtained by subjecting the etching foil to a chemical conversion treatment at a high chemical conversion voltage of≥500 V and has a high electrostatic capacitance and high mechanical strength. SOLUTION: The etching foil for aluminum electrolytic capacitors is obtained through an earlier stage etching treatment for forming pits in an aluminum foil by applying a direct current to the foil and a later stage etching treatment for expanding the pits. The etching foil for aluminum electrolytic capacitors having columnar pits extending in the thickness direction of the aluminum foil and characterized in that the ratio of the accumulated volume of pits to the volume of all the pits is≥30% for the pits each having a pit diameter of≥1.0μm and≤15% for the pits each having a pit diameter of≤0.5μm is obtained by setting the quantity of electricity applied to the aluminum foil in the later stage etching treatment to be larger than the quantity of electricity applied to the aluminum foil in the earlier stage etching treatment. COPYRIGHT: (C)2010,JPO&INPIT