Differential anodization process for electrolytic capacitor anode bodies
US6261434A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1999 |
| Grant date | Jul 17, 2001 |
| Priority date | — |
| Expiry date | Oct 19, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D11/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electrolyte comprising water, an organic solvent selected from the group consisting of a polyethylene glycol, a polyethylene glycol monomethyl ether and mixtures thereof, and a sufficient amount of alkali metal salt of a weak organic acid, so that the electrolyte has a resistivity below about 250 ohm-cm/80.degree. C. A method for differential anodizing porous valve metal body comprising the steps of: anodizing the bodies in a first electrolyte where the cathode surface is placed within an inch of but not in contact with the anode bodies, rinsing the bodies in deionized water, and re-anodizing the bodies in a second electrolyte, where the first electrolyte comprises water, an organic solvent selected from the group consisting of a polyethylene glycol, a polyethylene glycol monomethyl ether and mixtures thereof, and a sufficient amount of alkali metal salt of a weak organic acid so that the first electrolyte has a resistivity below about 250 ohm-cm/80.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.