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Patent US4767608A successfully refreshed from Google Patents.
US4767608A
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Method for synthesizing diamond by using plasma
Assignee: National Institute for Materials Science
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Filing: 1987-10-19
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Granted: 1988-08-30
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Expires: 2007-10-19
Abstract
Abstract A method for synthesizing diamond, which comprises: (a) generating a plasma by electric discharge in a gas selected from the group consisting of a hydrocarbon gas, hydrogen gas, an inert gas and a mixture thereof, (b) decomposing a carbon source by the plasma to form plasma gas containing carbon ions or carbon radicals, (c) effecting adiabatic expansion of the plasma gas to precipitate diamond.
Inventors
- 👤 Seiichiro Matsumoto
- 👤 Mototsugu Hino
- 👤 Yusuke Moriyoshi
- 👤 Takashi Nagashima
- 👤 Masayuki Tsutsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:59
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/22; C23C16/26; C23C16/27; C23C16/272; C01; C01B; C01B32/00; C01B32/25; C01B32/26; C23C16/274; C23C16/277; C23C16/44; C23C16/50; C23C16/513; C30; C30B; C30B25/00; C30B25/02; C30B25/10; C30B25/105; C30B29/00; C30B29/02; C30B29/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
67 words
A method for synthesizing diamond, which comprises: (a) generating a plasma by electric discharge in a gas selected from the group consisting of a hydrocarbon gas, a hydrogen gas, an inert gas and a mixture thereof, (b) decomposing a carbon source by the plasma to form a plasma gas containing carbon ions or carbon radicals, and (c) effecting adiabatic expansion of the plasma gas to precipitate diamond.
Claim 2
Independent Claim
67 words
A method for synthesizing diamond, which comprises: (a) generating a plasma by electric discharge in a gas selected from the group consisting of a hydrocarbon gas, a hydrogen gas, an inert gas and a mixture thereof, (b) decomposing a carbon source by the plasma to form a plasma gas containing carbon ions or carbon radicals, and (c) effecting adiabatic expansion of the plasma gas to precipitate diamond.
Claim 3
Dependent Claim
28 words
The method according to claim 1, wherein the adiabatic expansion is conducted by discharging the plasma gas from a nozzle or an orifice into a low pressure zone.
Claim 4
Dependent Claim
15 words
The method according to claim 1, wherein the diamond is precipitated in a gas phase.
Claim 5
Dependent Claim
14 words
The method according to claim 1, wherein the diamond is precipitated onto a substrate.
Claim 6
Dependent Claim
14 words
The method according to claim 1, wherein the inert gas is argon or helium.
Claim 7
Dependent Claim
31 words
The method according to claim 1, wherein the carbon source is an organic compound or carbon material capable of being decomposed to form carbon ions or carbon radicals in the plasma.
Claim 8
Dependent Claim
30 words
The method according to claim 1, wherein the carbon source is a hydrocarbon, a polymer, an oxygen, nitrogen, halogen, sulfur or phosphorus-containing organic compound, carbon monoxide, carbon dioxide, or graphite.
Claim 9
Dependent Claim
30 words
The method according to claim 1, wherein the carbon source is methane, ethane, propane, butane, ethylene, benzene, polyethylene, polypropylene, an alcohol, acetone, an amine, methyl chloride, thiophene or triethyl phosphine.
Claim 10
Dependent Claim
23 words
The method according to claim 1, wherein the plasma is generated at a gas pressure of from 10 -4 to 5×10 2 atm.
Claim 11
Dependent Claim
22 words
The method according to claim 1, wherein the diamond is precipitated at a gas pressure of from 10 -6 to 10 atm.
Claim 12
Dependent Claim
18 words
The method according to claim 1, wherein the gas temperature of the plasma is at least 1700° K.
Claim 13
Dependent Claim
29 words
A method according to claim 2, the nozzle or the orifice has a diameter of from 0.5 to 20 mm and a length of from 0.3 to 30 mm.
Claim 14
Dependent Claim
21 words
The method according to claim 3, wherein said gas phase is maintained at a temperature of from 400° to 1700° C.
Claim 15
Dependent Claim
20 words
The method according to claim 4, wherein the substrate is maintained at a temperature of from 400° to 1700° C.
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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) | 1991-08-30 | 1992-02-29 | 1992-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-30 | 1996-02-29 | 1996-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-30 | 2000-02-29 | 2000-08-30 | $7700.00 | Window Closed / Lapsed |