Patent US4127659A successfully refreshed from Google Patents.
US4127659A
Expired / Lapsed
US
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Silicon carbide filaments and method
Assignee: Avco Corp
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Filing: 1977-01-26
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Granted: 1978-11-28
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Expires: 1997-01-26
Abstract
Abstract A refractory substrate, which generally is graphite or carbon is overcoated with silicon carbide by chemical vapor deposition from gaseous sources of silicon and carbon. The deposition generally takes place in combination with hydrogen and the coating on the substrate generally has a thickness at least equal to the diameter of the substrate itself. A silicon carbide filament containing an inner and outer surface layer of carbon rich silicon carbide, together with a method of making the same, is described.
Inventors
- 👤 Harold E. Debolt
- 👤 Thomas W. Henze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:58
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/571; C04B41/45; C04B41/4584; C23; C23C; C23C16/00; C23C16/22; C23C16/30; C23C16/32; C23C16/325; D; D01; D01F; D01F11/00; D01F11/10; D01F11/12; D01F11/126; D01F8/00; D01F8/18; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/292; Y10T428/2929
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
122 words
A method of making high-strength silicon carbide filament in a continuous process comprising the steps of: passing a carbonaceous filament through a reactor; heating the filament to a temperature of 1400°-1500° C.; exposing the filament while at an elevated temperature to a mixture consisting essentially of a blend of dimethyldichlorosilane and monomethyldichlorosilane, hydrogen and a substance capable of releasing carbon when heated for forming a carbon rich silicon carbide coating on the filament; adding additional silane blend and hydrogen to said mixture to lower the temperature of said filament; and exposing the carbon rich silicon carbide coating to the mixture with said added silane and hydrogen for effecting the deposition of a silicon carbide coating on said carbon rich silicon carbide layer.
Claim 2
Independent Claim
122 words
A method of making high-strength silicon carbide filament in a continuous process comprising the steps of: passing a carbonaceous filament through a reactor; heating the filament to a temperature of 1400°-1500° C.; exposing the filament while at an elevated temperature to a mixture consisting essentially of a blend of dimethyldichlorosilane and monomethyldichlorosilane, hydrogen and a substance capable of releasing carbon when heated for forming a carbon rich silicon carbide coating on the filament; adding additional silane blend and hydrogen to said mixture to lower the temperature of said filament; and exposing the carbon rich silicon carbide coating to the mixture with said added silane and hydrogen for effecting the deposition of a silicon carbide coating on said carbon rich silicon carbide layer.
Claim 3
Dependent Claim
17 words
A method as described in claim 1 wherein said silicon carbide coating is formed at 1200°-1400° C.
Claim 4
Dependent Claim
41 words
A method as described in claim 2 wherein in addition an outer coating of carbon rich silicon carbide is deposited on the silicon carbide coating by raising the temperature of said filament and adding a source of carbon to said mixture.
Claim 5
Independent Claim
122 words
A method of making a high-strength silicon carbide filament in a continuous process comprising the steps of: passing a carbonaceous filament through a tubular reactor; exposing the filament while at an elevated temperature of 1400°-1500° C. to a mixture consisting essentially of a blend of dimethyldichlorisilane and monomethyldichlorisilane, hydrogen, argon, and a substance capable of releasing carbon when heated for depositing a carbon rich silicon carbide layer on the filament; diluting said argon and carbon in said mixture with additional silane and hydrogen for lowering the temperature of said filament; and exposing the carbon rich silicon carbide layer to said diluted mixture at said lower temperature for effecting the deposition of a silicon carbide coating on said carbon rich silicon carbide layer.
Claim 6
Independent Claim
122 words
A method of making a high-strength silicon carbide filament in a continuous process comprising the steps of: passing a carbonaceous filament through a tubular reactor; exposing the filament while at an elevated temperature of 1400°-1500° C. to a mixture consisting essentially of a blend of dimethyldichlorisilane and monomethyldichlorisilane, hydrogen, argon, and a substance capable of releasing carbon when heated for depositing a carbon rich silicon carbide layer on the filament; diluting said argon and carbon in said mixture with additional silane and hydrogen for lowering the temperature of said filament; and exposing the carbon rich silicon carbide layer to said diluted mixture at said lower temperature for effecting the deposition of a silicon carbide coating on said carbon rich silicon carbide layer.
Claim 7
Dependent Claim
15 words
A method as described in claim 4 wherein the diluent includes also nitrogen and air.
Claim 8
Dependent Claim
17 words
A method as described in claim 4 wherein said silicon carbide coating is formed at 1200°-1400° C.
Claim 9
Dependent Claim
41 words
A method as described in claim 4 wherein additional quantities of argon and a source of carbon are added to decrease the heat loss from said filament and for depositing a second carbon rich silicon carbide coating on said filament, respectively.
References Cited (Backward Citations)
US3391016A
Cited
US3437511A
Cited
US3850689A
Cited
US3496010A
Cited
US3553003A
Cited
US3677795A
Cited
US3738906A
Cited
US3924034A
Cited
US3811927A
Cited
US3811920A
Cited
US3877080A
Cited
US3925577A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-11-27 | 1982-05-29 | 1982-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-27 | 1986-05-29 | 1986-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-27 | 1990-05-29 | 1990-11-28 | $7700.00 | Window Closed / Lapsed |