Method of anodizing aluminum capacitor foil for use in low voltage, surface mount capacitors

US6540900B1 · kind B1 · utility

Assignee

• KEMET Electronics Corporation · US

Inventors

• John Tony Kinard · Greer, US
• Brian Melody · Greer, US
• Philip M. Lessner · Newberry, US
• Albert Kennedy Harrington · Mauldin, US
• David Alexander Wheeler · Williamston, US
• Erik Karlsen Reed · Mauldin, US
• Duane Earl Stenziner · Simpsonville, US

Key dates

• Filing date: Oct 16, 2001
• Grant date: Apr 1, 2003
• Expiry date: Oct 16, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25D11/12
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Disclosed is a process for the continuous anodizing of aluminum foil for use in aluminum electrolytic capacitors. Specifically, etched anode foil is anodized to relatively low voltage in a two-step reel-to-reel process. The process is particularly useful for anodizing highly-etched aluminum foil for use in surface mount aluminum capacitors containing conductive polymer cathode material. The process is economical and provides high foil quality. Specifically, the process for anodizing aluminum foil comprises anodizing the foil in a first electrolyte a solution, passing the foil through an oven, anodizing the foil in a second anodizing solution wherein the first electrolyte solution and second electrolyte solution each comprise about 5 wt % to about 50 wt % glycerine, about 0.01 wt % to about 0.2 wt % ammonium phosphate, and de-ionized water, and wherein the foil is anodized in the first electrolyte solution for at least 3.5 minutes