US4835207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preceramic compositions and ceramic products
Assignee: Albemarle Corp
•
Filing: 1987-11-13
•
Granted: 1989-05-30
•
Expires: 2007-11-13
Abstract
Abstract Low density SiC ceramics having improved bending and specific strengths are prepared by (A) intimately mixing about 50-85% by weight of SiC powder with about 15-50% by weight of a preceramic polysilazane binder, (B) pulverizing the mixture to form particles having a particle size smaller than 105 micrometers, (C) separating from those particles any particles having a particle size larger than about 105 micrometers, (D) molding the resultant composition having a particle size not larger than about 105 micrometers, and (E) pyrolyzing the molded composition in an inert atmosphere to a temperature of about 1200°-1450° C. In a preferred embodiment of the invention, the preceramic binder is at least one polysilazane prepared by reacting an organodihalosilane with ammonia, treating the ammonolysis product with a basic catalyst which is capable of deprotonating an NH group that is adjacent to an SiH group, and quenching the resultant product with an electrophilic quenching reagent.
Inventors
- 👤 John Semen
- 👤 John J. Rogers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:02
CPC Classifications
C; C08; C08L; C08L83/00; C08L83/16; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/571; C08K; C08K3/00; C08K3/10; C08K3/14; C08K3/34; C08G; C08G77/00; C08G77/60; C08G77/62
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
39 words
A preceramic composition having a particle size not larger than about 105 micrometers and comprising an intimate mixture of (A) about 50-85% by weight of SiC powder and (B) about 15-50% by weight of a preceramic solid polysilazane binder.
Claim 2
Dependent Claim
39 words
A preceramic composition having a particle size not larger than about 105 micrometers and comprising an intimate mixture of (A) about 50-85% by weight of SiC powder and (B) about 15-50% by weight of a preceramic solid polysilazane binder.
Claim 3
Dependent Claim
24 words
The composition of claim 1 wherein the SiC powder has a substantially spherical particle shape and a mean particle size of about 0.2-1.0 micrometer.
Claim 4
Dependent Claim
55 words
The composition of claim 1 wherein the binder consists essentially of at least one polysilazane prepared by reacting an organodihalosilane with ammonia, treating the ammonolysis product with a basic catalyst which is capable of deprotonating an NH group that is adjacent to an SiH group, and quenching the resultant product with an electrophilic quenching reagent.
Claim 5
Dependent Claim
22 words
The composition of claim 3 wherein the organodihalosilane is methyldichlorosilane, the basic catalyst is KH, and the quenching reagent is methyl iodide.
Claim 6
Dependent Claim
21 words
The composition of claim 3 wherein the organodihalosilane is methyldichlorosilane, the basic catalyst is KH, and the quenching reagent is dimethylchlorosilane.
Claim 7
Dependent Claim
16 words
The composition of claim 1 wherein the binder has an alkali metal content of 0-100 ppm.
Claim 8
Dependent Claim
14 words
The composition of claim 1 wherein the binder content is about 20-30% by weight.
Claim 9
Dependent Claim
85 words
The composition of claim 1 comprising an intimate mixture of (A) about 70-80% by weight of SiC powder having a substantially spherical particle shape and a mean particle size of about 0.2-1.0 micrometer and (B) about 20-30% by weight of a preceramic polysilazane binder which (1) has an alkali metal content of 0-5 ppm and (2) consists essentially of at least one polysilazane prepared by reacting methyldichlorosilane with ammonia, treating the ammonolysis product with KH, and quenching the resultant product with methyl iodide or dimethylchlorosilane.
Claim 10
Dependent Claim
54 words
A process which comprises intimately mixing about 50-85% by weight of SiC powder with about 15-50% by weight of a preceramic solid polysilazane binder, pulverizing the mixture to form particles having a particle size smaller than 105 micrometers, and separating from those particles any particles having a particle size larger than about 105 micrometers.
Claim 11
Dependent Claim
54 words
A process which comprises intimately mixing about 50-85% by weight of SiC powder with about 15-50% by weight of a preceramic solid polysilazane binder, pulverizing the mixture to form particles having a particle size smaller than 105 micrometers, and separating from those particles any particles having a particle size larger than about 105 micrometers.
Claim 12
Dependent Claim
51 words
The process of claim 9 wherein the SiC powder is dispersed in an organic solvent solution of the binder, the solvent is removed, and the resultant chunks of powder/binder are ball milled and then sieved to form an intimate powder/binder mixture having a particle size not larger than about 105 micrometers.
Claim 13
Dependent Claim
55 words
The process of claim 9 wherein the binder consists essentially of at least one polysilazane prepared by reacting an organodihalosilane with ammonia, treating the ammonolysis product with a basic catalyst which is capable of deprotonating an NH group that is adjacent to an SiH group, and quenching the resultant product with an electrophilic quenching reagent.
Claim 14
Dependent Claim
24 words
The proces of claim 9 wherein about 70-80% by weight of the SiC powder is mixed with about 20-30% by weight of the binder.
References Cited (Backward Citations)
US4117057A
Cited
US4560526A
Cited
US4482669A
Cited
US4645807A
Cited
US4639501A
Cited
US4650837A
Cited
US4659850A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-29 | 1992-11-28 | 1993-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-29 | 1996-11-28 | 1997-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-29 | 2000-11-28 | 2001-05-30 | $7700.00 | Window Closed / Lapsed |