Patent US4045186A successfully refreshed from Google Patents.
US4045186A
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Method for producing large soft hexagonal boron nitride particles
Assignee: General Electric Co
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Filing: 1976-12-06
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Granted: 1977-08-30
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Expires: 1996-12-06
Abstract
Abstract Soft hexagonal boron nitride crystals of 200-600 microns platelet size are produced from crystals of less than fifty microns particle size by mixing the small crystals with Li 3 N, simultaneously heating and pressurizing said mixture to a temperature and pressure in a restricted region of the graphitic (hexagonal) boron nitride (GBN) stable region of the pressure-temperature (P-T) phase diagram of boron nitride, cooling and depressurizing said mixture, and separating off the water soluble material present in the mixture to leave a residue of large crystals of boron nitride.
Inventors
- 👤 Francis R. Corrigan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:13
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C30; C30B; C30B29/00; C30B29/10; C30B29/38; C30B9/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
87 words
The method of producing soft hexagonal boron nitride crystals of larger than 50 microns average particle size which comprise the steps of: a. mixing graphitic boron nitride particles (GBN) of less than 50 microns average particle size and lithium nitride, the boron nitride comprising 50 to 85 mole percent of the boron nitride-lithium nitride mixture, b. simultaneously subjecting said mixture, and (d) separating the GBN crystals from the mixture to values of pressure and temperature within Region FBCE of the Figure; c. cooling and depressurizing said mixture.
Claim 2
Independent Claim
87 words
The method of producing soft hexagonal boron nitride crystals of larger than 50 microns average particle size which comprise the steps of: a. mixing graphitic boron nitride particles (GBN) of less than 50 microns average particle size and lithium nitride, the boron nitride comprising 50 to 85 mole percent of the boron nitride-lithium nitride mixture, b. simultaneously subjecting said mixture, and (d) separating the GBN crystals from the mixture to values of pressure and temperature within Region FBCE of the Figure; c. cooling and depressurizing said mixture.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein separation of said GBN is accomplished by an aquaeous solution and separation of water-soluble material.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein the recovered GBN crystals have an average particle size of at least 100 microns.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein said mixture is pressurized to a maximum pressure of about atmospheric pressure in step (b).
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein said mixture is subjected to said temperature and pressure of step (b) for a period of from twenty (20) minutes to four (4) hours.
Claim 7
Dependent Claim
27 words
The method of claim 6 wherein said GBN comprises about 43 weight percent of said mixture and the lithium nitride about 57 weight percent of said mixture.
Claim 8
Dependent Claim
27 words
The method of claim 1 wherein said mixture is subjected to said temperature and pressure of step (b) for a period in excess of twenty (20) minutes.
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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) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |