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Patent US4135937A successfully refreshed from Google Patents.
US4135937A
Expired / Lapsed
US
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High density hot pressed thermal shock resistant silicon carbide
Assignee: Unifrax I LLC
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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 method for making a dense thermal shock resistant silicon carbide ceramic body by hot pressing a blend of silicon carbide and from about 0.2 to about 2 weight percent of aluminum diboride and the resulting body.
Inventors
- 👤 Yorihiro Murata
- 👤 John A. Coppola
- 👤 Carl H. McMurtry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:23
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/575
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
44 words
A dense thermal shock resistant silicon carbide ceramic body which comprises a hot pressed composition comprising silicon carbide, from about 0.2 to about 2.0 weight percent of aluminum diboride and from about 150 to about 500 percent of carbon by weight of aluminum diboride.
Claim 2
Dependent Claim
44 words
A dense thermal shock resistant silicon carbide ceramic body which comprises a hot pressed composition comprising silicon carbide, from about 0.2 to about 2.0 weight percent of aluminum diboride and from about 150 to about 500 percent of carbon by weight of aluminum diboride.
Claim 3
Dependent Claim
23 words
The body claimed in claim 1 wherein said carbon is added in the form of an organic composition prior to said hot pressing.
Claim 4
Dependent Claim
22 words
The body claimed in claim 1 wherein said silicon carbide, prior to hot pressing, consists essentially of sub micron silicon carbide particles.
Claim 5
Independent Claim
109 words
A method for 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 5 microns with from about 0.2 to about 2 weight percent of particulate aluminum diboride having an average particle size below about ten microns and with from about 150 to 500 percent carbon by weight of aluminum diboride; and (b) hot pressing the blend at a sufficient temperature for a sufficient time and at a sufficient pressure to obtain a silicon carbide body having a density which is at least 99 percent of the theoretical density of solid silicon carbide.
Claim 6
Independent Claim
109 words
A method for 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 5 microns with from about 0.2 to about 2 weight percent of particulate aluminum diboride having an average particle size below about ten microns and with from about 150 to 500 percent carbon by weight of aluminum diboride; and (b) hot pressing the blend at a sufficient temperature for a sufficient time and at a sufficient pressure to obtain a silicon carbide body having a density which is at least 99 percent of the theoretical density of solid silicon carbide.
Claim 7
Dependent Claim
20 words
The method of claim 4 wherein said silicon carbide particles have an average particle size smaller than about 3 microns.
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
21 words
The method of claim 4 wherein said aluminum diboride consists essentially of particles having a size smaller than about 6 microns.
Claim 10
Dependent Claim
21 words
The method of claim 7 wherein said aluminum diboride consists essentially of particles having a size smaller than about 3 microns.
Claim 11
Dependent Claim
20 words
The method of claim 4 wherein the density is at least 99.7 percent of the theoretical density of silicon carbide.
Claim 12
Dependent Claim
20 words
The method of claim 4 wherein said sufficient pressure is from about 100 to about 1000 kilograms per square centimeter.
Claim 13
Dependent Claim
17 words
The method of claim 10 wherein said sufficient temperature is from about 1900° to about 2500° C.
Claim 14
Dependent Claim
18 words
The method of claim 11 wherein said sufficient time is from about 10 minutes to about 1 hour.
Claim 15
Dependent Claim
17 words
The method of claim 12 wherein said temperature is from about 1950° C. to about 2250° C.
Claim 16
Dependent Claim
20 words
The method of claim 13 wherein said sufficient pressure is between about 300 and about 400 kilograms per square centimeter.
Claim 17
Dependent Claim
17 words
The method of claim 14 wherein said sufficient time is between about 15 and about 45 minutes.
Claim 18
Dependent Claim
19 words
The method of claim 12 wherein the silicon carbide, aluminum diboride and carbon are blended in a ball mill.
Claim 19
Dependent Claim
20 words
The method of claim 12 wherein the hot pressing is carried out in an inert atmosphere or in a vacuum.
Claim 20
Dependent Claim
25 words
The method of claim 17 wherein the inert atmosphere comprises a gas selected from the group consisting of argon, nitrogen, hydrogen, helium and mixtures thereof.
Claim 21
Dependent Claim
10 words
The method of claim 18 wherein said gas is argon.
Claim 22
Dependent Claim
10 words
The method of claim 18 wherein said gas is nitrogen.
Claim 23
Dependent Claim
23 words
The method of claim 4 wherein said carbon is added as particulate carbon having an average particle size of less than 5 microns.
Claim 24
Dependent Claim
19 words
The method of claim 21 wherein said particulate carbon has an average particle size of less than 3 microns.
Claim 25
Dependent Claim
16 words
The method of claim 21 wherein said particulate carbon consists essentially of sub micron size particles.
Claim 26
Dependent Claim
28 words
The method of claim 1 wherein said carbon is added as a carbon compound consisting of elements selected from the group consisting of carbon, nitrogen, hydrogen and oxygen.
Claim 27
Dependent Claim
16 words
The method of claim 24 wherein the carbon compound is a high molecular weight aromatic compound.
Claim 28
Dependent Claim
13 words
The method of claim 24 wherein the carbon compound is an organic polymer.
Claim 29
Dependent Claim
13 words
The method of claim 26 wherein the carbon compound is a phenol-formaldehyde resin.
Claim 30
Dependent Claim
19 words
The method of claim 12 wherein from about 0.4 to about 1.0 weight percent of aluminum diboride is used.
References Cited (Backward Citations)
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 |