Patent US4818732A successfully refreshed from Google Patents.
US4818732A
Expired / Lapsed
US
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High surface area ceramics prepared from organosilane gels
Assignee: BP Corp North America Inc
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Filing: 1987-03-19
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Granted: 1989-04-04
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Expires: 2007-03-19
Abstract
Abstract High surface area open microporous, partially crystalline, partially amorphous, solid ceramic materials containing silicon carbide with or without silica with or without carbon may be prepared by controlled pyrolysis of (RSiO 1 .5) n gels in an inert atmosphere. The silica and carbon content, surface area, and pore size and distribution may be altered by optional subsequent processing steps to selectively remove carbon and/or silica.
Inventors
- 👤 Joseph R. Fox
- 👤 Douglas A. White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:54
CPC Classifications
C; C04; C04B; C04B38/00; C04B38/0045
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
125 words
A method for forming a high surface area, open microporous partially crystalline, partially amorphous solid ceramic material consisting essentially of silicon carbide comprising: (a) synthesis of a gel having the idealized formula (RSiO 1 .5) n wherein R equals vinyl, allyl, or phenyl, the gel being three dimensionally cross linked; (b) heating the gel at a rate of less than 10° C. per minute to a temperature of between 1200° C. and 1500° C. in an inert atmosphere and maintaining the temperature in the prescribed range until carbothermic reduction reaction to produce SiC proceeds to result in a high surface area, open microporous partially crystalline, partially amorphous solid ceramic material and thereafter reducing the temperature to ambient while maintaining the material in an inert atmosphere.
Claim 2
Independent Claim
125 words
A method for forming a high surface area, open microporous partially crystalline, partially amorphous solid ceramic material consisting essentially of silicon carbide comprising: (a) synthesis of a gel having the idealized formula (RSiO 1 .5) n wherein R equals vinyl, allyl, or phenyl, the gel being three dimensionally cross linked; (b) heating the gel at a rate of less than 10° C. per minute to a temperature of between 1200° C. and 1500° C. in an inert atmosphere and maintaining the temperature in the prescribed range until carbothermic reduction reaction to produce SiC proceeds to result in a high surface area, open microporous partially crystalline, partially amorphous solid ceramic material and thereafter reducing the temperature to ambient while maintaining the material in an inert atmosphere.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the gel is dried prior to the step of heating.
Claim 4
Dependent Claim
47 words
The method of claim 1 wherein the gel is prepared from alkoxy silanes having the general formula RSi(OR') 3 wherein R is a saturated or unsaturated hydocarbon group containing less than ten carbon atoms and R' is a saturated alkyl group containing less than five carbon atoms.
Claim 5
Dependent Claim
17 words
The method of claim 2 wherein the gel is prepared by acid-catalyzed hydrolysis followed by base-catalyzed condensation.
Claim 6
Dependent Claim
15 words
The method of claim 2 wherein the gel is prepared by base-catalyzed hydrolysis and condensation.
Claim 7
Dependent Claim
33 words
The method of claim 1 wherein the gel is prepared from chlorosilanes having the general formula RSiCl 3 wherein R is a saturated or unsaturated hydrocarbon group containing less than ten carbon atoms.
Claim 8
Dependent Claim
32 words
The method according to claim 2 wherein the dried gel is heated at a rate not exceeding 2° C. per minute while in the temperature range of 300° C. to 1500° C.
Claim 9
Dependent Claim
16 words
The method according to claim 4 wherein the inert atmosphere is deficient of nitrogen and oxygen.
References Cited (Backward Citations)
US31447A
Cited
US3856539A
Cited
US3947550A
Cited
US4041117A
Cited
US4097294A
Cited
US4154787A
Cited
US4238434A
Cited
USRE31447E
Cited
US4298559A
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US4414403A
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US4564496A
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US4626556A
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US4694040A
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US4497787A
Cited
US4608242A
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DE3516587A1
Cited
US4657843A
Cited
JPS60264365A
Cited
EP0171858A2
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US4690811A
Cited
US4639501A
Cited
JPH06110068A
Cited
JPH06114171A
Cited
JPH06117472A
Cited
JPH06153163A
Cited
JPH06183689A
Cited
JPH06191076A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |