Patent US4089931A successfully refreshed from Google Patents.
US4089931A
Expired / Lapsed
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Purification of boron nitride
Assignee: Motors Liquidation Co
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Filing: 1977-07-22
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Granted: 1978-05-16
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Expires: 1997-07-22
Abstract
Abstract Boron nitride (BN) is freed of boric oxide without increasing its electroconductivity by heating the BN under vacuum to evaporate the boric oxide and chlorinating the BN at a temperature sufficient to remove any elemental boron as boron trichloride.
Inventors
- 👤 Ram A. Sharma
- 👤 Thompson G. Bradley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:13
CPC Classifications
H; H01; H01M; H01M50/00; H01M50/40; H01M50/409; H01M50/44; C; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C01B21/0648; C01P; C01P2002/00; C01P2002/80; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
69 words
A process for purifying boron nitride to remove boric oxide therefrom without increasing the electrical conductivity of the boron nitride comprising the steps of: heating the boron nitride in a vacuum for a sufficient time and at a sufficient temperature to evaporate said boric oxide; and thereafter exposing the boron nitride to chlorine to chlorinate any elemental boron formed during said evaporation and drive it off as boron trichloride.
Claim 2
Dependent Claim
69 words
A process for purifying boron nitride to remove boric oxide therefrom without increasing the electrical conductivity of the boron nitride comprising the steps of: heating the boron nitride in a vacuum for a sufficient time and at a sufficient temperature to evaporate said boric oxide; and thereafter exposing the boron nitride to chlorine to chlorinate any elemental boron formed during said evaporation and drive it off as boron trichloride.
Claim 3
Dependent Claim
102 words
A process for removing boric oxide from boron nitride without increasing the electrical conductivity of the boron nitride comprising the steps of: heating the boron nitride in a vacuum to a temperature of about 1331° K. for a period sufficient to evaporate substantially all of said B 2 O 3 , the absolute pressure of said vacuum being less than the equilibrium vapor pressure of the B 2 O 3 at the specific temperature chosen; and thereafter heating the boron nitride in the presence of chlorine to chlorinate any elemental boron formed during said evaporation and drive it off as boron trichloride.
Claim 4
Dependent Claim
102 words
A process for removing boric oxide from boron nitride without increasing the electrical conductivity of the boron nitride comprising the steps of: heating the boron nitride in a vacuum to a temperature of about 1331° K. for a period sufficient to evaporate substantially all of said B 2 O 3 , the absolute pressure of said vacuum being less than the equilibrium vapor pressure of the B 2 O 3 at the specific temperature chosen; and thereafter heating the boron nitride in the presence of chlorine to chlorinate any elemental boron formed during said evaporation and drive it off as boron trichloride.
Claim 5
Dependent Claim
103 words
A process for purifying boron nitride to remove boric oxide therefrom without increasing the electrical conductivity of the boron nitride comprising the steps of: heating the boron nitride to a temperature of about 1775° K. to 1825° K. and at an absolute pressure of less than about 0.1 kPa for a time sufficient to evaporate substantially all of said B 2 O 3 therefrom; and thereafter heating the boron nitride to about 600° K. to about 800° K. in the presence of chlorine to chlorinate any boron formed during said B 2 O 3 evaporation step and drive it off as boron trichloride.
Claim 6
Dependent Claim
103 words
A process for purifying boron nitride to remove boric oxide therefrom without increasing the electrical conductivity of the boron nitride comprising the steps of: heating the boron nitride to a temperature of about 1775° K. to 1825° K. and at an absolute pressure of less than about 0.1 kPa for a time sufficient to evaporate substantially all of said B 2 O 3 therefrom; and thereafter heating the boron nitride to about 600° K. to about 800° K. in the presence of chlorine to chlorinate any boron formed during said B 2 O 3 evaporation step and drive it off as boron trichloride.
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) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |