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US4571331A
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Ultrafine powder of silicon carbide, a method for the preparation thereof and a sintered body therefrom
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1983-12-12
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Granted: 1986-02-18
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Expires: 2003-12-12
Abstract
Abstract The invention provides a method for the preparation of an ultrafine powder of silicon carbide having an extremely fine and uniform particle size distribution of spherical agglomerate particles each formed of crystallites of 5 nm or smaller in size. The silicon carbide powder is prepared by the vapor phase pyrolysis of a specified methyl hydrogen(poly)silane as diluted with a carrier gas, e.g. hydrogen, to give a concentration of 40% by volume or lower at a temperature of 750 DEG to 1600 DEG C. The silicon carbide powder can readily be sintered at a temperature of 1750 DEG to 2500 DEG C. even without addition of a sintering aid to give a sintered body of extremely high density reaching 80% or larger of the theoretical value which can never be obtained of the conventional silicon carbide powders.
Inventors
- 👤 Morinobu Endou
- 👤 Minoru Takamizawa
- 👤 Tatsuhiko Hongu
- 👤 Taishi Kobayashi
- 👤 Akira Hayashida
- 👤 Nobuaki Urasato
- 👤 Hiromi Ohsaki
- 👤 Nichiro Suzuki
- 👤 Takasi Toide
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:13
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/90; C01B32/914; C01B32/956; B; B82; B82Y; B82Y30/00; C01B32/963; C01B32/977; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/575; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2002/80; C01P2002/82; C01P2004/00; C01P2004/60; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/40
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
134 words
A method for preparation of a silicon carbide powder composed of polycrystalline agglomerate particles of silicon carbide each having a substantially spherical configuration of 0.01 to 1 μm diameter and formed of crystallites of β-type silicon carbide with a size of not exceeding 5 nm which comprises pyrolyzing, in a vapor phase, a methyl hydrogen(poly)silane compound represented by the general formula (CH 3 ) a Si b H c , in which the suffix b is 1, 2 or 3 and the suffixes a and c are related to b by the set of equations and inequalities 2b+1≧a, a≧b, 2b+1≧c≧1 and a+c=2b+2, diluted with a carrier gas to a concentration in the range from 0.2 to 40% by volume in the gaseous mixture at a temperature in the range from 750° to 1600° C.
Claim 2
Independent Claim
134 words
A method for preparation of a silicon carbide powder composed of polycrystalline agglomerate particles of silicon carbide each having a substantially spherical configuration of 0.01 to 1 μm diameter and formed of crystallites of β-type silicon carbide with a size of not exceeding 5 nm which comprises pyrolyzing, in a vapor phase, a methyl hydrogen(poly)silane compound represented by the general formula (CH 3 ) a Si b H c , in which the suffix b is 1, 2 or 3 and the suffixes a and c are related to b by the set of equations and inequalities 2b+1≧a, a≧b, 2b+1≧c≧1 and a+c=2b+2, diluted with a carrier gas to a concentration in the range from 0.2 to 40% by volume in the gaseous mixture at a temperature in the range from 750° to 1600° C.
Claim 3
Dependent Claim
24 words
The method as claimed in claim 1 wherein the carrier gas is hydrogen or a gaseous mixture of hydrogen with nitrogen, argon or helium.
Claim 4
Dependent Claim
65 words
The method as claimed in claim 1 wherein the methyl hydrogen(poly)silane is selected from the group consisting of methylsilane MeSiH 3 , dimethylsilane Me 2 SiH 2 , trimethylsilane Me 3 SiH, 1,2-dimethyldisilane, MeH 2 Si.SiH 2 Me, 1,1,2,2-tetramethyldisilane Me 2 HSi.SiHMe 2 , 1,1,2,3,3-pentamethyltrisilane Me 2 HSi.SiHMe.SiHMe 2 and 1,1,2,2,3,3-hexamethyltrisilane Me 2 HSi.SiMe 2 .SiHMe 2 , the symbol Me denoting a methyl group.
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) | 1989-02-17 | 1989-08-19 | 1990-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-17 | 1993-08-19 | 1994-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-17 | 1997-08-19 | 1998-02-18 | $7700.00 | Window Closed / Lapsed |