US3825469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boron carbide fiber production
Assignee: Unifrax I LLC
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Filing: 1972-07-03
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Granted: 1974-07-23
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Expires: 1992-07-03
Abstract
Abstract BORIC OXIDE FIBERS HAVING A MAXIMUM DIAMETER OF ABOUT 10 MICRONS ARE HEATED IN AN AMMONIA ATMOSPHERE TO ABOUT 350-600*C. AT A RATE OF TEMPERATURE RISE OF UP TO ABOUT 5000*C./HR. TO PRODUCE AMMONIA-TREATED FIBERS CONSISTING ESSENTIALLY OF B, N, O AND H. THE AMMONIATREATED FIBERS ARE HEATED IN AN AMINE ATMOSPHERE AT ABOUT 600-1000*C. TO PRODUCE AMINE-TREATED FIBERS CONSISTING ESSENTIALLY OF B, C, N, O AND H AND CONTAINING AT LEAST ABOUT 15% C. THE AMINE-TREATED FIBERS MAY BE HEATED AT ABOUT 2000-1350*C. IN AN INERT ATMOSPHERE TO PRODUCE BORON CARBIDE FIBERS.
Inventors
- 👤 J Economy
- 👤 V Matkovich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:40
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C04B35/62272; C04B35/62277; B; B01; B01J; B01J35/00; B01J35/50; B01J35/58; B01J37/00; C01; C01B; C01B32/00; C01B32/90; C01B32/914; C01B32/991; C04B35/62231; C04B35/62286; C04B35/6229; C04B35/626; C04B35/62605; C04B35/62645; C04B35/6265; C04B35/62675; C04B35/6268; C22; C22C; C22C49/00; C01P; C01P2006/00; C01P2006/10; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/34; C04B2235/3409; C04B2235/46; C04B2235/465; C04B2235/50; C04B2235/52; C04B2235/5208; C04B2235/5264; Y; Y10; Y10S; Y10S264/00; Y10S264/19; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2916; Y10T428/2918; Y10T428/298
Claims Analysis
Total Claims: 0
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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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |