Patent US3733291A successfully refreshed from Google Patents.
US3733291A
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US
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Formation process for producing dielectric aluminum oxide films
Assignee: Sprague Electric Co
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Filing: 1971-07-23
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Granted: 1973-05-15
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Expires: 1991-07-23
Abstract
Abstract A PROCESS FOR FORMING DIELECTRIC ALUMINUM OXIDE FILMS PRODUCES A FOIL SYSTEM THAT WILL NOT LOSE CAPACITANCE IN A WORKING ELECTROLYTE FOR FORMATIONS OF 50 V. OR MORE. AN ALUMINUM FOIL SURFACE HAS A HYDROUS OXIDE FORMED THEREIN, AND A BARRIER OXIDE LAYER ANODICALLY FORMED THROUGH THIS HYDROUS FILM. ANY EXCESS HYDROUS OXIDE REMAINING IS STRIPPED AWAY WITH A SOLUTION MADE UP OF H3PO4 AND CRO3, AND ON THIS SURFACE THE BARRIER OXIDE LAYER IS ANODICALLY REFORMED IN THE SAME MANNER AS IN THE ORIGINAL FORMATION. SUCH A FORMATION PROCESS CAN BE USED TO PRODUCE A UNIT HAVING A MUSH LOWER EQUIVALENT SERIES RESISTANCE THAN PRIOR ART UNITS.
Inventors
- 👤 R Alwitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:58
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/692; H10P14/6938; H10P14/6939; H10P14/69391; C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/06; C25D11/12; C25D11/16; H01; H01G; H01G9/00; H01G9/0029; H01G9/0032; H10P14/63; H10P14/6302; H10P14/6324; Y; Y10; Y10S; Y10S205/00; Y10S205/917
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |