US4719095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of silicon ceramic powders
Assignee: Toyota Motor Corp
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Filing: 1986-02-03
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Granted: 1988-01-12
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Expires: 2006-02-03
Abstract
Abstract A process for producing silicon ceramic powder, which comprises, oxidizing metallic silicon powder in an oxidizing gas atmosphere into silicon monoxide in the form of ultrafine particles or gas, and reducing said silicon monoxide in a reducing gas atmosphere containing at least nitrogen or carbon, thereby producing silicon nitride, silicon carbide or mixtures thereof.
Inventors
- 👤 Susumu Abe
- 👤 Masahiro Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:10
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/90; C01B32/914; C01B32/956; B; B82; B82Y; B82Y30/00; C01B21/00; C01B21/06; C01B21/068; C01B32/963; C01B32/97; C01B33/00; C01B33/113; C01P; C01P2004/00; C01P2004/60; C01P2004/64
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
56 words
A process for producing silicon ceramic powder, which comprises: (a) oxidizing metallic silicon powder in an oxidizing gas atmosphere into silicon monoxide in the form of ultrafine particles or gas; and (b) reducing said silicon monoxide in a reducing gas atmosphere containing at least nitrogen or carbon, thereby producing silicon nitride, silicon carbide or mixtures thereof.
Claim 2
Dependent Claim
56 words
A process for producing silicon ceramic powder, which comprises: (a) oxidizing metallic silicon powder in an oxidizing gas atmosphere into silicon monoxide in the form of ultrafine particles or gas; and (b) reducing said silicon monoxide in a reducing gas atmosphere containing at least nitrogen or carbon, thereby producing silicon nitride, silicon carbide or mixtures thereof.
Claim 3
Dependent Claim
30 words
The process of claim 1, wherein said reduction is continously conducted as the oxidation continuously proceeds, and the heat from the oxidation step provides the energy for the reduction process.
Claim 4
Dependent Claim
38 words
The process of claim 1, wherein said oxidation step is conducted by forming a dust cloud from metallic silicon powder and an oxidizing gas, and then igniting the dust cloud to cause explosive burning of the silicon powder.
Claim 5
Dependent Claim
18 words
The process of claim 1, wherein said reducing gas is a mixture of a hydrocarbon gas and ammonia.
Claim 6
Dependent Claim
13 words
The process of claim 1, wherein said reducing gas is a hydrocarbon gas.
Claim 7
Dependent Claim
19 words
The process of claim 1, wherein the ignition is accomplished by means of a burner or a plasma jet.
Claim 8
Dependent Claim
18 words
The process of claim 1, wherein the metallic silicon powder has a particle diameter smaller than 200 mesh.
Claim 9
Dependent Claim
18 words
The process of claim 1, wherein the nitrogen-containing reducing gas is preheated prior to reducing said silicon monoxide.
Claim 10
Dependent Claim
21 words
The process of claim 1, wherein said silicon ceramic powder product has a particle size of 100 Å to 1000 Å.
Claim 11
Dependent Claim
77 words
A process for producing silicon ceramic powder, which comprises: (a) forming a dust cloud of metallic silicon and an oxidizing gas; (b) explosively oxidizing said silicon dust thereby forming silicon monoxide in the form of ultrafine particles or a gas; and (c) reducing said silicon monoxide in a reducing gas atmosphere containing at least nitrogen or carbon, thereby producing silicon nitride, silicon carbide or mixtures thereof in a particle size range of 100 Å to 1000 Å.
Claim 12
Dependent Claim
77 words
A process for producing silicon ceramic powder, which comprises: (a) forming a dust cloud of metallic silicon and an oxidizing gas; (b) explosively oxidizing said silicon dust thereby forming silicon monoxide in the form of ultrafine particles or a gas; and (c) reducing said silicon monoxide in a reducing gas atmosphere containing at least nitrogen or carbon, thereby producing silicon nitride, silicon carbide or mixtures thereof in a particle size range of 100 Å to 1000 Å.
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) | 1991-01-11 | 1991-07-13 | 1992-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-11 | 1995-07-13 | 1996-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-11 | 1999-07-13 | 2000-01-12 | $7700.00 | Window Closed / Lapsed |