USRE27083E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sintered transparent bodies of alumin- ium oxide and method of preparing the same
Assignee: —
•
Filing: 1969-03-12
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Granted: 1971-03-02
•
Expires: 1989-03-12
Abstract
Abstract A DENSE POLYCRYSTALLINE BODY OF ALUMINUM OXIDE HAVING AN AVERAGE GRAIN SIZE OF LESS THAN TEN MICRONS, AT LEAST 80 PERCENT OF THE GRAINS BEING SMALLER THAN 7 MICRONS, YET HAVING HIGH LIGHT TRANSMISSIVITY IS OBTAINED FROM ALUMINUM OXIDE PARTICLES GROUND TO A SIZE OF ABOUT 3 MICRONS OR LESS UNTIL THEIR X-RAY DIFFRACTION SPECTRUM IS PRACTICALLY FREE OF KA DOUBLETS BY SINTERING THE PARTICLES AT 1700* TO 1950*C. IN A VACUUM FOR A FEW MINUTES ONLY.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:22
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |