US3640887A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transparent zirconia- hafnia- and thoria-rare earth ceramics
Assignee: General Electric Co
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Filing: 1970-04-06
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Granted: 1972-02-08
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Expires: 1990-04-06
Abstract
Abstract THE MANUFACTURE OF TRANSPARENT POLYCRYSTALLINE CERAMIC BODIES COMPOSED OF OXIDES OF THORIUM, ZIRCONIUM, AND HAFNIUM AND MIXTURES THEREOF WITH OXIDES OF THE RATE EARTH ELEMENTS 58 THROUGH 71 OF THE PERIODIC TALBE AND MIXTURES THEREOF WITH OR WITHOUT YTTRIA, WHEREIN THE CERAMIC BODY IS IN THE CUBIC CRYSTAL SYSTEM, THE AVERAGE IONIC RADIUS OF THE RARE EARTH OXIDE WITH OR WITHOUT THE YTTRIA IS NO GREATER THAN ABOUT 0.93 A., AND THE DIFFERENCE IN IONIC SIZES OF THE OXIDES IS NO GREATER THAN ABOUT 0.22 A. IS DISCLOSED.
Inventors
- 👤 Richard C Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:18
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50
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) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |