Patent US3910388A successfully refreshed from Google Patents.
US3725533A
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Boron carbide fiber production
Assignee: Unifrax I LLC
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Filing: 1969-11-14
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Granted: 1973-04-03
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Expires: 1989-11-14
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 5,000*C/hr. to produce ammonia-treated fibers consisting essentially of B, N. O and H. The ammonia-treated fibers are heated in an amine atmosphere at about 600*-1,000*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 2,000*-2,350*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
2026-11-05 06:05
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C04B35/62272; C04B35/62286; C04B35/6229; B; B01; B01J; B01J35/00; B01J35/50; B01J35/58; B01J37/00; C04B35/62231; C04B35/62277; C04B35/626; C04B35/62605; C04B35/62645; C04B35/6265; C04B35/62675; C04B35/6268; C22; C22C; C22C49/00; C01; C01P; C01P2006/00; C01P2006/10; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/46; C04B2235/465; C04B2235/50; C04B2235/52; C04B2235/5208; C04B2235/5264; Y; Y10; Y10S; Y10S264/00; Y10S264/19
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
24 words
A process as set forth in claim 1 wherein said heating in an ammonia atmosphere is begun at a starting temperature below about 250*C.
Claim 2
Dependent Claim
19 words
A process as set forth in claim 2 wherein said rate of temperature rise is at least about 5*C/hr.
Claim 3
Dependent Claim
21 words
A process as set forth in claim 2 wherein said rate of temperature rise is between about 10*C/hr. and about 100*C/hr.
Claim 4
Dependent Claim
24 words
A process as set forth in claim 1 wherein said amine is selected from the group consisting of methylamine, dimethylamine, trimethylamine, ethylamine and allylamine.
Claim 5
Dependent Claim
13 words
A process as set forth in claim 1 wherein said amine is methylamine.
Claim 6
Dependent Claim
13 words
A process as set forth in claim 2 wherein said amine is methylamine.
Claim 7
Dependent Claim
27 words
A process as set forth in claim 7 wherein said temperature of said heating in an atmosphere of an amine is between about 700*C and about 800*C.
Claim 8
Dependent Claim
25 words
A process as set forth in claim 8 wherein said temperature of said heating in an inert atmosphere is between about 2,200*C and about 2,300*C.
References Cited (Backward Citations)
US1501419A
Cited
US3429722A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |