US3707589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reheating a beta-alumina article in an alkali metal atmosphere to improve its permeability
Assignee: Toyota Central R&D Labs Inc
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Filing: 1971-04-13
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Granted: 1972-12-26
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Expires: 1991-04-13
Abstract
Abstract A BETA-ALUMINA ARTICLE PERMEABLE TO SODIUM AND POTASSIUM IONS MADE BY HEATING A SINTERED ALPHA-ALUMINA ARTICLE IN THE PRESENCE OF SODIUM OR POTASSIUM SUFFERS FROM A LACK OF UNIFORMITY OF CONVERSION OF ALPHA-ALUMINA TO BETA-ALUMINA, PARTICULARY IN THE CENTER PORTION OF THE ARTICLE. THE UNIFORMITY IS GREATLY IMPROVED BY REHEATING THIS ARTICLE AT SIMILAR TEMPERATURES USED IN THE FIRST HEATING STEP IN AN ATMOSPHERE HAVING A LOWER CONCENTRATION OF SODIUM OR POTASSIUM THAN USED IN T HE FIRST HEATING STEP. FOLLOWING THIS SECOND HEATING STEP THE ARTICLE IS WASHED IN WATER.
Inventors
- 👤 Takewo Chiku
- 👤 Kiyoshi Ninomiya
- 👤 Hiroaki Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:15
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/113; H; H01; H01M; H01M10/00; H01M10/36; H01M10/39; H01M10/3909; H01M10/3918; Y; Y02; Y02E; Y02E60/00; Y02E60/10
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) | 1975-12-26 | 1976-06-26 | 1976-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-26 | 1980-06-26 | 1980-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-26 | 1984-06-26 | 1984-12-26 | $7700.00 | Window Closed / Lapsed |