US4332652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
AC Etching of aluminum capacitor foil
Assignee: Sprague Electric Co
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Filing: 1981-07-06
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Granted: 1982-06-01
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Expires: 2001-07-06
Abstract
Abstract Aluminum electrolytic capacitor foil is etched in a bath containing 0.5 to 1.8 M hydrochloric acid, 0.2 to 0.5 M aluminum chloride, 0.03 to 0.3 M phosphoric acid, and 0.05 to 0.3 M nitric acid, the molar ratio of said nitric acid to said phosphoric acid being 0.3-5, while subjected to the action of alternating current at 28 DEG to 45 DEG C.
Inventors
- 👤 Mulk R. Arora
- 👤 Edward J. Paquette
- 👤 Allan B. McPherson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:46
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: 6
Claim 1
Independent Claim
58 words
A process for AC electrolytic etching of aluminum capacitor foil comprising passing the foil between electrodes supplied with alternating current at a frequency of 12 to 30 Hz in a bath comprising hydrochloric acid, nitric acid, phosphoric acid, and aluminum chloride at 28° to 45° C., the molar ratio of said nitric to said phosphoric acid being 0.3-5.
Claim 2
Dependent Claim
58 words
A process for AC electrolytic etching of aluminum capacitor foil comprising passing the foil between electrodes supplied with alternating current at a frequency of 12 to 30 Hz in a bath comprising hydrochloric acid, nitric acid, phosphoric acid, and aluminum chloride at 28° to 45° C., the molar ratio of said nitric to said phosphoric acid being 0.3-5.
Claim 3
Dependent Claim
18 words
A process according to claim 1 wherein the molar ratio of nitric acid to hydrochloric acid is 1:3-12.
Claim 4
Dependent Claim
35 words
A process according to claim 1 wherein said bath comprises 0.5 to 1.8 M hydrochloric acid, 0.05 to 0.3 M nitric acid, 0.03 to 0.3 M phosphoric acid, and 0.2 to 0.5 M aluminum chloride.
Claim 5
Dependent Claim
18 words
A process according to claim 1 wherein the anodic current density is 1.0 to 3.6 A/in 2 .
Claim 6
Dependent Claim
70 words
A process according to claim 1 wherein the concentration of the hydrochloric acid is 0.7 to 1.5 M, the concentration of the nitric acid is about 0.15 M, the concentration of the phosphoric acid is about 0.11 M, the concentration of the aluminum chloride is about 0.25 to 0.4 M, the temperature is 32° to 38° C., and the frequency of the alternating current is about 20 to 26 Hz.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-31 | 1985-11-30 | 1986-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-31 | 1989-11-30 | 1990-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-31 | 1993-11-30 | 1994-06-01 | $7700.00 | Window Closed / Lapsed |