US4252575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Producing hydrous oxide of controlled thickness on aluminum capacitor foil
Assignee: UNITED CHEMI-CON MANUFACTURING Inc
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Filing: 1979-08-09
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Granted: 1981-02-24
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Expires: 1999-08-09
Abstract
Abstract The thickness of a hydrous oxide layer on aluminum capacitor foil is controlled by producing the oxide in a hot, dilute borate solution with a pH of about 6, prior to anodization of the foil.
Inventors
- 👤 Walter J. Bernard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:37
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/16; C23; C23C; C23C22/00; C23C22/05; C23C22/68
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
69 words
A process for controlling the thickness of a hydrous oxide layer formed on aluminum electrolytic capacitor foil comprising forming said hydrous layer of controlled thickness in a hot dilute aqueous borate solution consisting essentially of 1 to 6 g/l boric acid and sufficient borax to provide a pH of 5.5 to 7.0 for 1 to 10 minutes to provide a weight increase of up to 0.8 mg/cm 2 .
Claim 2
Dependent Claim
69 words
A process for controlling the thickness of a hydrous oxide layer formed on aluminum electrolytic capacitor foil comprising forming said hydrous layer of controlled thickness in a hot dilute aqueous borate solution consisting essentially of 1 to 6 g/l boric acid and sufficient borax to provide a pH of 5.5 to 7.0 for 1 to 10 minutes to provide a weight increase of up to 0.8 mg/cm 2 .
Claim 3
Dependent Claim
29 words
A process according to claim 1 wherein said borate solution contains 2 to 6 g/l of boric acid and sufficient borax to provide a pH of 5.7 to 6.5.
Claim 4
Dependent Claim
25 words
A process according to claim 2 wherein said pH is 6 and the temperature of said solution is between 95° C. and its boiling point.
Claim 5
Dependent Claim
33 words
A process according to claim 3 wherein the residence time is 3 minutes, said boric acid concentration is 3.5 g/l, and said borax concentration is 6.0 mg/l to provide said pH of 6.
Claim 6
Dependent Claim
12 words
A process according to claim 1 wherein said foil is etched foil.
Claim 7
Dependent Claim
44 words
A process according to claim 1 wherein said foil with said hydrous oxide thereon is immersed in an aqueous solution between 95° C. and its boiling point of a phosphate or a partly neutralized silicate to modify said hydrous oxide layer and increase capacitance.
Claim 8
Dependent Claim
36 words
A process according to claim 6 wherein said aqueous phosphate solution has a pH of 5 to 7 and said silicate solution has been partially neutralized by a tartrate to a pH of 7 to 12.
Claim 9
Dependent Claim
17 words
A process according to claim 7 wherein said silicate solution has a pH of 10 to 11.
Claim 10
Dependent Claim
19 words
A process according to claim 7 wherein the residence time in said aqueous solution is 2 to 12 minutes.
Claim 11
Dependent Claim
15 words
A process according to claim 9 wherein said residence time is 6 to 8 minutes.
References Cited (Backward Citations)
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US2079516A
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US2404824A
Cited
US2868702A
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US3600245A
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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) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |