US4781993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber reinforced ceramic material
Assignee: United States, NATIONAL AERONAUTICS AND SPACE ADMINSTRATION THE, Administrator of
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Filing: 1987-04-15
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Granted: 1988-11-01
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Expires: 2007-04-15
Abstract
Abstract A strong and tough SiC/RBSN composite material comprises silicon fibers and a reaction bonded silicon nitride matrix. This composite material may be used at elevated temperatures up to at least 1400 DEG C.
Inventors
- 👤 Ramakrishna T. Bhatt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:32
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/515; C04B35/58; C04B35/584; C04B35/591; C04B35/65; C04B35/71; C04B35/78; C04B35/80; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249924; Y10T428/249928; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/2933; Y10T428/294; Y10T428/296; Y10T428/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
76 words
An improved composite material for use at elevated temperatures up to at least 1400° C. comprising a plurality of mats of silicon carbide fibers, each of said fibers comprising a pyrolitic graphite coated carbon core, a silicon carbide sheath covering said coated carbon core, an amorphous carbon layer covering said silicon carbide sheath and an overlayer having a high silicon/carbon ratio covering said amorphous carbon layer, and a silicon nitride matrix reaction bonded to said fibers.
Claim 2
Dependent Claim
76 words
An improved composite material for use at elevated temperatures up to at least 1400° C. comprising a plurality of mats of silicon carbide fibers, each of said fibers comprising a pyrolitic graphite coated carbon core, a silicon carbide sheath covering said coated carbon core, an amorphous carbon layer covering said silicon carbide sheath and an overlayer having a high silicon/carbon ratio covering said amorphous carbon layer, and a silicon nitride matrix reaction bonded to said fibers.
Claim 3
Dependent Claim
23 words
An improved composite material as claimed in claim 1 wherein the pyrolitic graphite coated carbon core has a diameter of about 37 μm.
Claim 4
Dependent Claim
21 words
An improved composite material as claimed in claim 2 wherein the silicon carbide sheath has a diameter of about 142 μm.
Claim 5
Dependent Claim
22 words
An improved composite material as claimed in claim 1 wherein the silicon carbide fibers comprise about 23 volume fraction of the composite.
Claim 6
Dependent Claim
22 words
An improved composite material as claimed in claim 1 wherein the silicon carbide fibers comprise about 40 volume fraction of the composite.
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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) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |