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US4428916A
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Method of making α-silicon nitride powder
Assignee: Toshiba Corp
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Filing: 1979-09-26
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Granted: 1984-01-31
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Expires: 1999-09-26
Abstract
Abstract α-Silicon nitride powder which is used as a raw material for the preparation of high strength silicon nitride with additives such as magnesia and yttrium oxide, and other sintered materials suitable for high temperatures gas turbine engine components and the like, is prepared by heating a powdered mixture of silica, carbon and at least one component selected from the group consisting of silicon nitride, silicon carbide and silicon oxynitride in a nitrogen containing atmosphere and then optionally subjecting the material to a heat treatment in an oxidizing atmosphere for decarbonization of said material as required.
Inventors
- 👤 Katsutoshi Komeya
- 👤 Hiroshi Inoue
- 👤 Shigeru Matake
- 👤 Hiroshi Endo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:15
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/068; C01B21/0685; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2004/62; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
81 words
A method of manufacturing α-silicon nitride which comprises the steps of: (a) premixing 1 wt. part silica powder, 0.4-4 wt. parts carbon powder and 0.005-1.0 wt. part of at least one powder component selected from the group consisting of silicon nitride, silicon carbide and silicon oxynitride; and (b) heating said mixture at from 1350° C. to 1550° C. in a non-oxidizing atmosphere containing at least one of nitrogen or ammonia, for a time sufficient to effect the formation of α-silicon nitride.
Claim 2
Independent Claim
81 words
A method of manufacturing α-silicon nitride which comprises the steps of: (a) premixing 1 wt. part silica powder, 0.4-4 wt. parts carbon powder and 0.005-1.0 wt. part of at least one powder component selected from the group consisting of silicon nitride, silicon carbide and silicon oxynitride; and (b) heating said mixture at from 1350° C. to 1550° C. in a non-oxidizing atmosphere containing at least one of nitrogen or ammonia, for a time sufficient to effect the formation of α-silicon nitride.
Claim 3
Dependent Claim
29 words
The method of claim 1, which further comprises the step of heating said α-silicon nitride at from 600° C. to 800° C. in an oxidizing atmosphere to effect decarbonization.
Claim 4
Dependent Claim
11 words
The method of claim 1, wherein said component is silicon nitride.
Claim 5
Dependent Claim
12 words
The method of claim 3, wherein said silicon nitride is α-silicon nitride.
Claim 6
Dependent Claim
13 words
The method of claim 1, wherein said non-oxidizing atmosphere is N 2 gas.
Claim 7
Dependent Claim
13 words
The method of claim 1, wherein said non-oxidizing atmosphere is NH 3 gas.
Claim 8
Dependent Claim
19 words
The method of claim 1, wherein said non-oxidizing atmosphere is a mixture of N 2 and H 2 gas.
Claim 9
Dependent Claim
18 words
The method of claim 1, wherein said non-oxidizing atmosphere is a mixture of N 2 and Ar gas.
Claim 10
Dependent Claim
11 words
The method of claim 2, wherein said oxidizing atmosphere is air.
Claim 11
Dependent Claim
11 words
The method of claim 1, wherein said component is silicon carbide.
Claim 12
Dependent Claim
11 words
The method of claim 1, wherein said component is silicon oxynitride.
Claim 13
Dependent Claim
21 words
The method of claim 1, wherein said silica and said carbon have an average grain diameter not greater than 1 μm.
Claim 14
Dependent Claim
18 words
The method of claim 1, wherein said component has an average grain diameter not greater than 2 μm.
Claim 15
Dependent Claim
18 words
The method of claim 13, wherein said component has an average grain diameter not greater than 0.5 μm.
Claim 16
Dependent Claim
15 words
The method of claim 1, wherein said component has a purity of at least 99%.
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) | 1987-01-30 | 1987-08-01 | 1988-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-30 | 1991-08-01 | 1992-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-30 | 1995-08-01 | 1996-01-31 | $7700.00 | Window Closed / Lapsed |