US4279714A
Expired / Lapsed
US
⏱️ 0.0 years remaining
AC Etching of aluminum capacitor
Assignee: Sprague Electric Co
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Filing: 1980-09-15
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Granted: 1981-07-21
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Expires: 2000-09-15
Abstract
Abstract Aluminum electrolytic capacitor foil is etched in a bath containing 0.7 to 2.O M hydrochloric acid, 0.2 to 0.5 M hydrated aluminum trichloride, and 0.02 to 0.4 M phosphate ion while subjected to the action of alternating current at 35 to 55 DEG C.
Inventors
- 👤 Mulk A. Arora
- 👤 John J. Randall, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:56
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/04; H01G9/048; H01G9/055; C; C25; C25F; C25F3/00; C25F3/02; C25F3/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
53 words
A process for the electrolytic etching of aluminum electrolytic capacitor foil comprising passing the foil between electrodes supplied with alternating current in a bath containing 0.7 to 2 moles/liter hydrochloric acid, 0.2 to 0.5 moles/liter hydrated aluminum trichloride, and 0.02 to 0.4 moles/liter phosphate ion at a temperature of 35° to 55° C.
Claim 2
Dependent Claim
53 words
A process for the electrolytic etching of aluminum electrolytic capacitor foil comprising passing the foil between electrodes supplied with alternating current in a bath containing 0.7 to 2 moles/liter hydrochloric acid, 0.2 to 0.5 moles/liter hydrated aluminum trichloride, and 0.02 to 0.4 moles/liter phosphate ion at a temperature of 35° to 55° C.
Claim 3
Dependent Claim
29 words
A process according to claim 1 wherein the anodic current density is 1.6 to 4 amps/in 2 and the frequency of the alternating current is 20 to 40 Hz.
Claim 4
Dependent Claim
41 words
A process according to claim 1 wherein the concentration of said hydrochloric acid is 1.4 M, the concentration of said hydrated aluminum chloride is 0.4 M, the concentration of said phosphate ion is 0.2 M, and said temperature is 45° C.
Claim 5
Dependent Claim
15 words
A process according to claim 1 wherein the etching time is 2 to 6 minutes.
References Cited (Backward Citations)
US3193485A
Cited
US3887447A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-20 | 1985-01-19 | 1985-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-20 | 1989-01-19 | 1989-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-20 | 1993-01-19 | 1993-07-21 | $7700.00 | Window Closed / Lapsed |