US4769064A
Expired / Lapsed
US
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Method for synthesizing ultrafine powder materials
Assignee: United States Department of Energy
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Filing: 1988-01-21
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Granted: 1988-09-06
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Expires: 2008-01-21
Abstract
Abstract A method for synthesizing ultrafine powder materials, for example, ceramic and metal powders, comprises admitting gaseous reactants from which the powder material is to be formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400° K. (127°C.). The gaseous reactants are directed through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material.
Inventors
- 👤 Richard J. Buss
- 👤 Pauline Ho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:32
CPC Classifications
B; B22; B22F; B22F9/00; B22F9/02; B22F9/14; B01; B01J; B01J12/00; B01J12/02; B01J19/00; B01J19/08; B01J19/087; B01J19/088; B22F9/16; B22F9/30; C; C01; C01B; C01B21/00; C01B21/06; C01B21/068; C01B32/00; C01B32/05; C01P; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
64 words
A method for synthesizing ultrafine powder material from gaseous reactants, comprising (a) admitting gaseous reactants from which the powder material is formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400° K., and directing the gaseous reactants through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material.
Claim 2
Independent Claim
64 words
A method for synthesizing ultrafine powder material from gaseous reactants, comprising (a) admitting gaseous reactants from which the powder material is formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400° K., and directing the gaseous reactants through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material.
Claim 3
Dependent Claim
21 words
A method as defined by claim 1, wherein the reaction chamber is maintained at a pressure greater than about 200 mTorr.
Claim 4
Dependent Claim
29 words
A method as defined by claim 1, wherein the reaction chamber is maintained at a pressure of about 500 mTorr and a temperature of less than about 400° K.
Claim 5
Dependent Claim
17 words
A method as defined by claim 1, wherein the glow discharge is generated through radio frequency energy.
Claim 6
Dependent Claim
29 words
A method as defined by claim 4, wherein the radio frequency energy is at a frequency of approximately 13.56 Megahertz and the average power density is about 0.05 watts/cc.
Claim 7
Dependent Claim
22 words
A method as defined by claim 1, including the additional step of collecting the ultrafine powder material produced in the glow discharge.
Claim 8
Dependent Claim
27 words
A method as defined by claim 6, wherein the ultrafine powder material is collected on a filter member arranged between the glow discharge and the vacuum source.
Claim 9
Dependent Claim
23 words
A method as defined by claim 1, wherein the ultrafine powder material has an average particle diameter of less than about 2000 Å.
Claim 10
Dependent Claim
23 words
A method as defined by claim 8, wherein the ultrafine powder material has an average particle size of less than about 500 Å.
Claim 11
Dependent Claim
16 words
A method as defined by claim 1, wherein the ultrafine powder material comprises a ceramic powder.
Claim 12
Dependent Claim
16 words
A method as defined by claim 1, wherein the ultrafine powder material comprises a metal powder.
Claim 13
Dependent Claim
28 words
A method as defined by claim 1, wherein the gaseous reactants consist essentially of silane and ammonia and the ultrafine powder material consists essentially of silicon nitride powder.
Claim 14
Dependent Claim
14 words
A method as defined by claim 12, wherein the silicon nitride powder is amorphous.
Claim 15
Dependent Claim
28 words
A method as defined by claim 1, wherein the gaseous reactants consist essentially of tungsten hexafluoride and hydrogen and the ultrafine powder material consists essentially of tungsten powder.
Claim 16
Dependent Claim
23 words
A method as defined by claim 14, wherein the flow ratio of tungsten hexafluoride to hydrogen into the reaction chamber is about 1:7.
Claim 17
Dependent Claim
26 words
A method as defined by claim 1, wherein the gaseous reactants consist essentially of acetylene and the ultrafine powder material consists essentially of amorphous hydrogenated carbon.
Claim 18
Dependent Claim
12 words
The ultrafine powder material prepared according to the method of claim 1.
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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) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |