Patent US3709981A successfully refreshed from Google Patents.
US3709981A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refractory compounds
Assignee: Evonik LIL Ltd
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Filing: 1970-08-20
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Granted: 1973-01-09
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Expires: 1990-08-20
Abstract
Abstract THIS INVENTION RELATES TO REFRACTORY COMPOUNDS AND SPECIFICALLY TO A PROCESS OF PREPARING SILICON CARBIDE. THE PROCESS COMPRISES REACTING, IN A REACTION ZONE, AT AN ELEVATED TEMPERATURE SILICA, ELEMETARY CARBON, A SOURCE OF SULPHUR, HYDROGEN AND A GASEOUS SOURCE OF CARBON, WHEREBY SILICON CARBIDE IS FROMED IN A CONDENSATION ZONE. THE SOURCE OF CARBON MAY BE A HYDROCARBON OR CARBON MONOXIDE OR A CARBON/SULPHUR COMPOUND
Inventors
- 👤 S Lee
- 👤 C Cardy
- 👤 K Sampson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:16
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C30; C30B; C30B25/00; C30B25/005; C30B29/00; C30B29/10; C30B29/36
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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |