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US4781874A
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Process for making silicon nitride articles
Assignee: Eaton Corp
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Filing: 1987-10-23
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Granted: 1988-11-01
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Expires: 2007-10-23
Abstract
Abstract A process for making silicon nitride articles such as an internal combustion valve (8) by coating or causing silicon to grow on powdered silicon nitride particles through a vapor phase reaction and then forming and nitriding the articles in substantially less time than had the article been formed entirely from powdered silicon.
Inventors
- 👤 James P. Edler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:38
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/591
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
72 words
A process for making a silicon nitride article, said process including the steps of: (a) providing powdered alpha-silicon nitride particles; (b) coating the articles of step (a) with metallic silicon by means of a vapor phase reaction; (c) forming the coated particles of step (b) into the article; and (d) nitriding the article of step (c) at a temperature and for a time effective to convert the metallic silicon to silicon nitride.
Claim 2
Dependent Claim
72 words
A process for making a silicon nitride article, said process including the steps of: (a) providing powdered alpha-silicon nitride particles; (b) coating the articles of step (a) with metallic silicon by means of a vapor phase reaction; (c) forming the coated particles of step (b) into the article; and (d) nitriding the article of step (c) at a temperature and for a time effective to convert the metallic silicon to silicon nitride.
Claim 3
Dependent Claim
16 words
The process of claim 1 including the step of sintering the nitrided article of step (d).
Claim 4
Dependent Claim
63 words
The process of claim 1 wherein the coating of step (b) is provided by aspirating the particles of step (a) into a mixture of argon and a minor amount of trihlorosilane to provide a gaseous slurry and then flowing the gaseous slurry through a furnace at a temperature and for a period of time effective to decompose the trichlorosilane into the metallic silicon.
Claim 5
Dependent Claim
53 words
The process of claim 1 wherein the coating of step (b) is provided by aspirating the particles of step (a) into a mixture of argon containing a minor amount of silane to provide a gaseous slurry and thence exposing the slurry to ultra-violet radiation effective to decompose the silane into the metallic silicon.
Claim 6
Dependent Claim
45 words
The process of claim 1 wherein the coating of step (b) is provided by mixing the alpha-silicon nitride particles of step (a) with argon and trichlorosilane and thence exposing the mixture to a plasma arc torch effective to decompose the trichlorosilane into the metallic silicon.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |