US4419335A
Expired / Lapsed
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Process for producing rhombohedral system boron nitride
Assignee: National Institute for Materials Science
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Filing: 1982-03-10
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Granted: 1983-12-06
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Expires: 2002-03-10
Abstract
Abstract Rhombohedral system boron nitride is produced by heating a boron material selected from the group consisting of boron oxide, boric acid and an oxygen-containing boron compound capable of forming boron oxide when heated, at a temperature of from 1200° to 2100° C. to vaporize boron oxide and reacting the vaporized boron oxide with hydrogen cyanide or cyanogen gas.
Inventors
- 👤 Toshihiko Ishii
- 👤 Tadao Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:37
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C01P; C01P2002/00; C01P2002/70; C01P2002/72
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
66 words
A process for producing high-purity rhombohedral system boron nitride, having good crystallinity, which comprises heating a boron material selected from the group consisting of boron oxide, boric acid and an oxygen-containing boron compound capable of forming boron oxide when heated, at a temperature of from 1200° to 2100° C., thereby vaporizing the boron oxide and reacting the vaporized boron oxide with hydrogen cyanide or cyanogen gas.
Claim 2
Dependent Claim
66 words
A process for producing high-purity rhombohedral system boron nitride, having good crystallinity, which comprises heating a boron material selected from the group consisting of boron oxide, boric acid and an oxygen-containing boron compound capable of forming boron oxide when heated, at a temperature of from 1200° to 2100° C., thereby vaporizing the boron oxide and reacting the vaporized boron oxide with hydrogen cyanide or cyanogen gas.
Claim 3
Dependent Claim
32 words
The process according to claim 1 wherein said hydrogen cyanide is introduced in a form of a reducing gas containing hydrogen cyanide obtained by the reaction of nitrogen, water-containing gas and carbon.
Claim 4
Dependent Claim
18 words
The process according to claim 1 wherein said boron material is mixed with boron nitride or alumina powder.
Claim 5
Dependent Claim
24 words
The process according to claim 1 wherein said hydrogen cyanide or cyanogen gas is introduced together with a reducing gas or an inert gas.
Claim 6
Dependent Claim
21 words
The process according to claim 1 wherein said hydrogen cyanide or cyanogen gas is introduced together with nitrogen, ammonia or hydrogen.
Claim 7
Dependent Claim
27 words
The process according to claim 1 wherein said hydrogen cyanide or cyanogen gas is introduced in a form of a coal gas or water gas containing it.
Claim 8
Dependent Claim
21 words
The process according to claim 1 wherein said hydrogen cyanide or cyanogen gas is introduced together with carbon monoxide and ammonia.
Claim 9
Dependent Claim
22 words
The process according to claim 1 wherein said hydrogen cyanide or cyanogen gas is introduced together with hydrogen carbide, ammonia and oxygen.
Claim 10
Dependent Claim
21 words
The process according to claim 1 wherein said boron material is heated at a temperature of from 1500° to 1900° C.
Claim 11
Dependent Claim
16 words
The process according to claim 1 wherein said oxygen-containing boron compound is borax or ammonium borate.
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) | 1986-12-05 | 1987-06-06 | 1987-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-05 | 1991-06-06 | 1991-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-05 | 1995-06-06 | 1995-12-06 | $7700.00 | Window Closed / Lapsed |