Patent CH258679A successfully refreshed from Google Patents.
Patent US5268201A successfully refreshed from Google Patents.
US5268201A
Expired / Lapsed
US
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Composite diamond grain and method for production thereof
Assignee: Resonac Holdings Corp
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Filing: 1991-05-13
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Granted: 1993-12-07
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Expires: 2011-05-13
Abstract
Abstract A composite diamond grain which comprises a heat-resistant grain as a nucleus and discrete diamond crystal particles distributed on the surface of the grain or diamond crystal films formed to cover the entire surface of the grain and a method for producing the composite diamond grain by the vapor-phase process are disclosed. For the filament method which is one form of the vapor-phase method, tantalum is useful as the material for the filament. Since tantalum is susceptible of embrittlement by hydrogen, a treatment to be performed on tantalum for the elimination of this drawback is also disclosed.
Inventors
- 👤 Kunio Komaki
- 👤 Takashi Fujimaki
- 👤 Masaaki Yanagisawa
- 👤 Yoichi Hirose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:40
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/22; C23C16/26; C23C16/27; C23C16/277; C23C16/271; C30; C30B; C30B25/00; C30B25/02; C30B29/00; C30B29/02; C30B29/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
182 words
A method for the production of a composite diamond grain, comprising the steps of: setting in a reaction vessel for synthesis of diamond a tantalum filament; introducing an inert gas into the reaction vessel to induce an atmosphere containing the inert gas; introducing a carbon compound gas and hydrogen gas into the atmosphere so that the insert gas has a concentration of at least 20% by volume and the carbon compound gas has a concentration of at least 0.01% by volume in terms of methane while heating the tantalum filament to a temperature in the range of 1600° C. to 2800° C. to deprive the tantalum filament of strain and make the tantalum filament resistant to embrittlement and susceptible to carbonization; setting in the reaction vessel a container containing therein a heat-resistant grain for crystallization of diamond; introducing a gaseous raw material for formation of diamond into the resultant atmosphere while adjusting the temperature of the tantalum filament, thereby exciting the atmosphere to a diamond-forming atmosphere; and fluidizing the heat-resistant grain to deposit diamond crystals on the surface of the heat-resistant grain.
Claim 2
Independent Claim
182 words
A method for the production of a composite diamond grain, comprising the steps of: setting in a reaction vessel for synthesis of diamond a tantalum filament; introducing an inert gas into the reaction vessel to induce an atmosphere containing the inert gas; introducing a carbon compound gas and hydrogen gas into the atmosphere so that the insert gas has a concentration of at least 20% by volume and the carbon compound gas has a concentration of at least 0.01% by volume in terms of methane while heating the tantalum filament to a temperature in the range of 1600° C. to 2800° C. to deprive the tantalum filament of strain and make the tantalum filament resistant to embrittlement and susceptible to carbonization; setting in the reaction vessel a container containing therein a heat-resistant grain for crystallization of diamond; introducing a gaseous raw material for formation of diamond into the resultant atmosphere while adjusting the temperature of the tantalum filament, thereby exciting the atmosphere to a diamond-forming atmosphere; and fluidizing the heat-resistant grain to deposit diamond crystals on the surface of the heat-resistant grain.
Claim 3
Dependent Claim
18 words
The method according to claim 1, wherein said heat-resistant grain has a diameter of at least 30 μm.
Claim 4
Dependent Claim
52 words
The method according to claim 1, wherein the temperature of said tantalum filament for exciting the inert-gas atmosphere in the reaction vessel to the diamond-forming atmosphere is in the range of 1600° C. to below 2250° C. and the diamond crystals deposited on the surface of the heat-resistant grain are discrete crystals.
Claim 5
Dependent Claim
21 words
The method according to claim 3, wherein said discrete crystals occupy 10 to 90% of the surface of said heat-resistant grain.
Claim 6
Dependent Claim
56 words
The method according to claim 1, wherein the temperature of said tantalum filament for exciting the inert-gas atmosphere in the reaction vessel to the diamond-forming atmosphere is not less than 2250° C. and the diamond crystals deposited on the surface of the heat-resistant grain are compact crystal films covering the entire surface of said heat-resistant grain.
Claim 7
Independent Claim
186 words
A method for the production of a composite diamond grain, comprising the steps of: setting in a reaction vessel for synthesis of diamond a tantalum filament and a container containing therein a heat-resistant grain for crystallization of diamond so that the heat-resistant grain can be fluidized; introducing an inert gas into the reaction vessel to induce an atmosphere containing the inert gas; introducing a carbon compound gas and hydrogen gas into the atmosphere so that the inert gas has a concentration of at least 20% by volume and the carbon compound gas has a concentration of at least 0.01% by volume in terms of methane while heating the tantalum filament to a temperature in the range of 1600° C. to 2800° C. to deprive the tantalum filament of strain and make the tantalum filament resistant to embrittlement and susceptible to carbonization; introducing a gaseous raw material for formation of diamond into the resultant atmosphere while adjusting the temperature of the tantalum filament, thereby exciting the atmosphere to a diamond-forming atmosphere; and fluidizing the heat-resistant grain to deposit diamond crystals on the surface of the heat-resistant grain.
Claim 8
Independent Claim
186 words
A method for the production of a composite diamond grain, comprising the steps of: setting in a reaction vessel for synthesis of diamond a tantalum filament and a container containing therein a heat-resistant grain for crystallization of diamond so that the heat-resistant grain can be fluidized; introducing an inert gas into the reaction vessel to induce an atmosphere containing the inert gas; introducing a carbon compound gas and hydrogen gas into the atmosphere so that the inert gas has a concentration of at least 20% by volume and the carbon compound gas has a concentration of at least 0.01% by volume in terms of methane while heating the tantalum filament to a temperature in the range of 1600° C. to 2800° C. to deprive the tantalum filament of strain and make the tantalum filament resistant to embrittlement and susceptible to carbonization; introducing a gaseous raw material for formation of diamond into the resultant atmosphere while adjusting the temperature of the tantalum filament, thereby exciting the atmosphere to a diamond-forming atmosphere; and fluidizing the heat-resistant grain to deposit diamond crystals on the surface of the heat-resistant grain.
Claim 9
Dependent Claim
18 words
The method according to claim 6, wherein said heat-resistant grain has a diameter of at least 30 μm.
Claim 10
Dependent Claim
52 words
The method according to claim 6, wherein the temperature of said tantalum filament for exciting the inert-gas atmosphere in the reaction vessel to the diamond-forming atmosphere is in the range of 1600° C. to below 2250° C. and the diamond crystals deposited on the surface of the heat-resistant grain are discrete crystals.
Claim 11
Dependent Claim
21 words
The method according to claim 8, wherein said discrete crystals occupy 10 to 90% of the surface of said heat-resistant grain.
Claim 12
Dependent Claim
56 words
The method according to claim 6, wherein the temperature of said tantalum filament for exciting the inert-gas atmosphere in the reaction vessel to the diamond-forming atmosphere is not less than 2250° C. and the diamond crystals deposited on the surface of the heat-resistant grain are compact crystal films covering the entire surface of said heat-resistant grain.
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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) | 1996-12-06 | 1997-06-07 | 1997-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-06 | 2001-06-07 | 2001-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-06 | 2005-06-07 | 2005-12-07 | $7700.00 | Window Closed / Lapsed |