Patent US4680278A successfully refreshed from Google Patents.
US4680278A
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Process for preparing aluminum nitride powder
Assignee: Toshiba Corp
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Filing: 1985-12-23
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Granted: 1987-07-14
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Expires: 2005-12-23
Abstract
Abstract A process for preparing aluminum nitride powder, which comprises mixing (i) aluminum hydroxide powder, (ii) carbon powder or a substance capable of forming carbon powder by heating and (iii) at least one of additives selected from the group consisting of aluminum nitride powder, silicon nitride powder, silicon carbide powder and powder of substances capable of forming the powder corresponding to these powders, and baking the mixture thus obtained in a non-oxidative atmosphere containing nitrogen. The process is useful for preparing aluminum nitride powder having small particle size and small particle size distribution and also having a uniform shape of particles, at a lower temperature and in a shorter period of time.
Inventors
- 👤 Hiroshi Inoue
- 👤 Akihiko Tsuge
- 👤 Katsutoshi Komeya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:36
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/072; C01B21/0726; C01B21/082; C01B21/0821; C01B21/0826; C01P; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
74 words
A process for preparing aluminum nitride powder, which comprises mixing (i) aluminum hydroxide powder, (ii) carbon powder or a substance capable of forming carbon powder by heating and (iii) at least one of additives selected from the group consisting of aluminum nitride powder, silicon nitride powder, silicon carbide powder and powder of substances capable of forming the powder corresponding to these powders, and baking the mixture thus obtained in a non-oxidative atmosphere containing nitrogen.
Claim 2
Dependent Claim
74 words
A process for preparing aluminum nitride powder, which comprises mixing (i) aluminum hydroxide powder, (ii) carbon powder or a substance capable of forming carbon powder by heating and (iii) at least one of additives selected from the group consisting of aluminum nitride powder, silicon nitride powder, silicon carbide powder and powder of substances capable of forming the powder corresponding to these powders, and baking the mixture thus obtained in a non-oxidative atmosphere containing nitrogen.
Claim 3
Dependent Claim
46 words
The process according to claim 1, wherein said carbon powder and said at least one additive are mixed in amounts of 0.2 to 2.0 parts by weight and 0.005 to 1.0 part by weight, respectively, based on 1 part by weight of said aluminum hydroxide powder.
Claim 4
Dependent Claim
20 words
The process according to claim 1, wherein said mixture is baked at a temperature of from 1300° to 1850° C.
Claim 5
Dependent Claim
26 words
The process according to claim 1, wherein said carbon powder has a particle size of 0.5 μm or less and said additive, 1.0 μm or less.
Claim 6
Dependent Claim
20 words
The process according to claim 1, wherein said aluminum hydroxide powder has a particle size of 20 to 1.0 μm.
Claim 7
Dependent Claim
18 words
The process according to claim 1, wherein said additive has a particle size of 3.0 μm or less.
Claim 8
Dependent Claim
16 words
The process according to claim 1, wherein said mixture is baked for 2 to 20 hours.
Claim 9
Dependent Claim
33 words
The process according to claim 1, further comprising the step of baking the baked product at a temperature of from about 600° to 800° C. in an oxidative atmosphere to remove remaining carbon.
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) | 1990-07-13 | 1991-01-12 | 1991-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-13 | 1995-01-12 | 1995-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-13 | 1999-01-12 | 1999-07-14 | $7700.00 | Window Closed / Lapsed |