Claims
- 1. A method of manufacturing an electrode foil for an aluminum electrolytic capacitor, comprising:a first etching step in which an aluminum foil is immersed in an etching solution of an acidic aqueous solution containing hydrochloric acid and sulfuric acid and/or nitric acid, and supplied with direct current, thereby to form main pits; a middle etching step in which an etching is performed by using an etching solution of neutral salt containing an additive, and by supplying a direct current, thereby to effectively form sub pits branched away from the main pits at midpoints or inner ends thereof except at a surface layer portion thereof; and a final etching step for increasing the main pits and the sub pits in diameter.
- 2. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 1, wherein at least one or more additives are selected from chromic acid, oxalic acid, citric acid, phosphoric acid, boric acid, succinic acid, and malonic acid.
- 3. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 1, wherein the additive has a concentration of 0.01 to 1.0%.
- 4. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 1, wherein in the middle etching step, when etching is performed by supplying a direct current, DC etching is performed by passing the aluminum foil through a pair of electrode plates in a plurality of etching tanks each having a plurality of pairs of electrode plates, and AC etching is performed by providing a pair of electrode plates for supplying an alternating current at an upper or lower position of at least a pair of electrode plates among a plurality of pairs of electrode plates provided in the plurality of etching tanks.
- 5. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 4, wherein a pair of electrode plates for supplying a direct current is provided immediately after the pair of electrode plates for supplying an alternating current.
- 6. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 4, wherein the pair of electrode plates for supplying an alternating current is provided to partially interrupt a pair of electrode plates for supplying a direct current.
- 7. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 4, wherein the pair of electrode plates for supplying an alternating current is 0.01 to 0.15 A/cm2 in current density.
- 8. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 1, wherein in the first etching step and/or final etching step, etching is performed by supplying a direct current such that DC etching is performed by passing the aluminum foil through a pair of electrode plates in a plurality of etching tanks each having a plurality of pairs of electrode plates, and DC etching is performed while an electrical insulating material partially interrupts at least a pair of electrode plates among the plurality of pairs of electrode plates provided in the plurality of etching tanks.
- 9. The method of manufacturing an electrode foil for an aluminum electrolytic capacitor according to claim 8, wherein the electrical insulating material includes an opening composed of a plurality of holes or a plurality of slits.
Priority Claims (2)
Number |
Date |
Country |
Kind |
2001-36544 |
Feb 2001 |
JP |
|
2001-53994 |
Feb 2001 |
JP |
|
Parent Case Info
This application is a divisional of application Ser. No. 10/073,860 filed Feb. 14, 2002, now abandoned.
US Referenced Citations (8)