Patent US5114693A successfully refreshed from Google Patents.
US5114693A
Expired / Lapsed
US
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Process for the production of silicon nitride and product made according to the process
Assignee: Alzchem Trostberg GmbH
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Filing: 1991-05-09
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Granted: 1992-05-19
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Expires: 2011-05-09
Abstract
Abstract The present invention provides a process for the production of silicon nitride by the reaction of silicon and nitrogen, wherein, in one reaction step, silicon powder is reacted with nitrogen which continuously rotates at a temperature of from 1000° to 1800° C. and at a pressure of from 1.01 to 1.8 bar up to a nitrogen content of 1 to 39.5% by weight. The present invention also provides a silicon nitride produced by this process wherein it is obtained in porous form and has the following properties. a) grain size of 0.1 to 20 mm. b) nitrogen content of 1 to 39.5% by weight, c) oxygen content of 1%, d) ratio of α:β-phase of 1:9 to 9:1.
Inventors
- 👤 Jochen Hintermayer
- 👤 Ernst Graf
- 👤 Werner Gmohling
- 👤 Georg Schroll
- 👤 Wolfgang Kobler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:51
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/068; C01B21/0682; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C01P; C01P2004/00; C01P2004/50; C01P2006/00; C01P2006/14
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
93 words
A process for the production of silicon nitride by the reaction of silicon and nitrogen, said process comprising the step of: reacting silicon powder having a particle size of less than 45 microns and a silicon content of at least 95% with nitrogen while said silicon is continuously rotated at a temperature of from 1000° C. to 1800° C. and at a pressure of from 1.01 to 1.8 bar to produce silicon nitride having a nitrogen content of from 1 to 39.5% by weight and a ratio of α:β-phase of 1:9 to 9:1.
Claim 2
Dependent Claim
93 words
A process for the production of silicon nitride by the reaction of silicon and nitrogen, said process comprising the step of: reacting silicon powder having a particle size of less than 45 microns and a silicon content of at least 95% with nitrogen while said silicon is continuously rotated at a temperature of from 1000° C. to 1800° C. and at a pressure of from 1.01 to 1.8 bar to produce silicon nitride having a nitrogen content of from 1 to 39.5% by weight and a ratio of α:β-phase of 1:9 to 9:1.
Claim 3
Dependent Claim
24 words
A process according to claim 1, wherein the reaction is carried out up to a nitrogen content of from 5 to 25% by weight.
Claim 4
Dependent Claim
16 words
A process according to claim 1, wherein the reaction is carried out in a rotating tube.
Claim 5
Dependent Claim
21 words
A process according to claim 1, wherein a silicon powder is used with a grain size of less than 20 microns.
Claim 6
Dependent Claim
19 words
A process according to claim 1, wherein a silicon powder is used with a silicon content greater than 97.5%.
Claim 7
Dependent Claim
26 words
A process according to claim 1 wherein said step of reacting silicon powder With nitrogen is continued for a period of from 2 to 60 minutes.
Claim 8
Dependent Claim
80 words
The process of claim 1, wherein said step of reacting silicon powder with nitrogen is further characterized in that said step is allowed to continue only up to the production of a partly nitrided product having a nitrogen content of from 5 to 25% by weight and after said step of reacting silicon powder with nitrogen said process further includes the step of reacting the partly nitrided product at a temperature of 1100° C. to 1600° C. with nitrogen gas.
Claim 9
Dependent Claim
60 words
The process of claim 7 wherein the step of reacting said partly nitrided product is further characterized in that said partly nitrided product is reacted with a mixture of nitrogen and an inert gas, wherein the concentration of said nitrogen and said inert gas in said mixture change as said step of reacting said partly nitrided product continues to completion.
Claim 10
Dependent Claim
26 words
The process according to claim 8 wherein said step of reacting the partly nitrided product is carried out in a chamber furnace in a stationary bed.
Claim 11
Dependent Claim
27 words
The process of claim 8 wherein said step of reacting said partly nitrided product is further characterized in that said inert gas in said mixture is argon.
Claim 12
Dependent Claim
54 words
The process of claim 8 wherein the step of reacting the partly nitrided product is further characterized in that the proportion of nitrogen in said mixture is adjusted to 30 to 70% by volume and increased to 100% by volume of nitrogen as said step of reacting the partly nitrided product continues to completion.
Claim 13
Dependent Claim
29 words
The process of claim 1 wherein the step of reacting silicon powder with nitrogen is carried out up to a nitrogen content of from 5 to 25% by weight.
Claim 14
Dependent Claim
10 words
Silicon nitride produced according to the process of claim 1.
Claim 15
Dependent Claim
10 words
Silicon nitride produced according to the process of claim 7.
Claim 16
Dependent Claim
10 words
Silicon nitride produced according to the process of claim 7.
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) | 1995-05-19 | 1995-11-18 | 1996-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-19 | 1999-11-18 | 2000-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-19 | 2003-11-18 | 2004-05-19 | $7700.00 | Window Closed / Lapsed |