US4135938A
Expired / Lapsed
US
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High density thermal shock resistant sintered silicon carbide
Assignee: Stemcor Corp
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Filing: 1977-03-31
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Granted: 1979-01-23
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Expires: 1997-03-31
Abstract
Abstract A dense thermal shock resistant silicon carbide ceramic body and its method of manufacture which comprises heat sintering a shaped body comprising particulate silicon carbide and an additive selected from boron nitride, boron phosphide, aluminum diboride and mixtures thereof.
Inventors
- 👤 Yorihiro Murata
- 👤 John A. Coppola
- 👤 Carl H. McMurtry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:58
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
30 words
A dense thermal shock resistant silicon carbide ceramic body which comprises a pressureless sintered composition comprising silicon carbide, and from about 0.3 to about 3 weight percent of aluminum diboride.
Claim 2
Dependent Claim
30 words
A dense thermal shock resistant silicon carbide ceramic body which comprises a pressureless sintered composition comprising silicon carbide, and from about 0.3 to about 3 weight percent of aluminum diboride.
Claim 3
Dependent Claim
24 words
The body claimed in claim 1 wherein said composition further contains from about 150 to about 500 percent carbon by weight of aluminum diboride.
Claim 4
Dependent Claim
22 words
The body claimed in claim 1 wherein said carbon is added in the form of an organic composition prior to said sintering.
Claim 5
Dependent Claim
22 words
The body claimed in claim 1 wherein said silicon carbide, prior to said sintering, consists essentially of sub micron silicon carbide particles.
Claim 6
Independent Claim
112 words
A method of making a dense thermal shock resistant silicon carbide ceramic body which comprises: (a) blending silicon carbide consisting essentially of particles having a particle size below about 3 microns with from about 0.3 to about 3 weight percent of aluminum diboride and with from about 150 to about 500 percent carbon by weight of additive; (b) forming the blend into a shaped body; and (c) heating the shaped body in an inert environment at a temperature of from about 1900° C. to about 2500° C. for a time sufficient to obtain a ceramic body having a density of at least 85 percent of the theoretical density of solid silicon carbide.
Claim 7
Independent Claim
112 words
A method of making a dense thermal shock resistant silicon carbide ceramic body which comprises: (a) blending silicon carbide consisting essentially of particles having a particle size below about 3 microns with from about 0.3 to about 3 weight percent of aluminum diboride and with from about 150 to about 500 percent carbon by weight of additive; (b) forming the blend into a shaped body; and (c) heating the shaped body in an inert environment at a temperature of from about 1900° C. to about 2500° C. for a time sufficient to obtain a ceramic body having a density of at least 85 percent of the theoretical density of solid silicon carbide.
Claim 8
Dependent Claim
16 words
The method of claim 5 wherein said silicon carbide consists essentially of sub micron size particles.
Claim 9
Dependent Claim
24 words
The method of claim 6 wherein said aluminum diboride is a particulate solid having essentially all particles of a size below about 3 microns.
Claim 10
Dependent Claim
15 words
The method of claim 7 wherein the aluminum diboride consists essentially of sub micron particles.
Claim 11
Dependent Claim
17 words
The method of claim 7 wherein said heating time is from about 30 to about 90 minutes.
Claim 12
Dependent Claim
19 words
The method of claim 7 wherein the silicon carbide, aluminum diboride and carbon are blended in a ball mill.
Claim 13
Dependent Claim
28 words
The method of claim 7 wherein the blend is pressed at a pressure of from about 100 kilograms per square centimeter to about 2000 kilograms per square centimeter.
Claim 14
Dependent Claim
28 words
The method of claim 11 wherein the blend is pressed at a pressure of from about 350 kilograms per square centimeter to about 1400 kilograms per square centimeter.
Claim 15
Dependent Claim
20 words
The method of claim 11 wherein the inert environment comprises an atomsphere of argon, nitrogen, hydrogen, helium or mixtures thereof.
Claim 16
Dependent Claim
11 words
The method of claim 13 wherein the inert atmosphere is argon.
Claim 17
Dependent Claim
11 words
The method of claim 13 wherein the inert atmosphere is nitrogen.
Claim 18
Dependent Claim
24 words
The method of claim 11 wherein the inert environment is a vacuum below about 1 × 10 -3 mm of mercury of pressure absolute.
Claim 19
Dependent Claim
15 words
The method of claim 13 wherein the density is at least 95 percent of theoretical.
Claim 20
Dependent Claim
27 words
The method of claim 11 wherein the carbon is added as carbon compound consisting of elements selected from the group consisting of carbon, nitrogen, hydrogen and oxygen.
Claim 21
Dependent Claim
17 words
The method of claim 18 wherein the carbon compound is a high molecular weight aromatic organic compound.
Claim 22
Dependent Claim
13 words
The method of claim 19 wherein the carbon compound is an organic polymer.
Claim 23
Dependent Claim
13 words
The method of claim 20 wherein the polymer is a phenol formaldehyde resin.
Claim 24
Dependent Claim
17 words
The method of claim 13 wherein the temperature is from about 2000° C. to about 2100° C.
Claim 25
Dependent Claim
30 words
A dense thermal shock resistant silicon carbide ceramic body which comprises a pressureless sintered composition comprising silicon carbide, and from about 0.3 to about 3 weight percent of boron nitride.
Claim 26
Dependent Claim
30 words
A dense thermal shock resistant silicon carbide ceramic body which comprises a pressureless sintered composition comprising silicon carbide, and from about 0.3 to about 3 weight percent of boron nitride.
Claim 27
Independent Claim
112 words
A method of making a dense thermal shock resistant silicon carbide ceramic body which comprises: (a) blending silicon carbide consisting essentially of particles having a particle size below about 3 microns with from about 0.3 to about 3 weight percent of boron nitride and with from about 150 to about 500 percent carbon by weight of additive; (b) forming the blend into a shaped body; and (c) heating the shaped body in an inert environment at a temperature of from about 1900° C. to about 2500° C. for a time sufficient to obtain a ceramic body having a density of at least 85 percent of the theoretical density of solid silicon carbide.
Claim 28
Independent Claim
112 words
A method of making a dense thermal shock resistant silicon carbide ceramic body which comprises: (a) blending silicon carbide consisting essentially of particles having a particle size below about 3 microns with from about 0.3 to about 3 weight percent of boron nitride and with from about 150 to about 500 percent carbon by weight of additive; (b) forming the blend into a shaped body; and (c) heating the shaped body in an inert environment at a temperature of from about 1900° C. to about 2500° C. for a time sufficient to obtain a ceramic body having a density of at least 85 percent of the theoretical density of solid silicon carbide.
Claim 29
Dependent Claim
16 words
The method of claim 24 wherein said silicon carbide consists essentially of sub micron size particles.
References Cited (Backward Citations)
US4004934A
Cited
US4031178A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-22 | 1982-07-24 | 1983-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-22 | 1986-07-24 | 1987-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-22 | 1990-07-24 | 1991-01-23 | $7700.00 | Window Closed / Lapsed |