US3718490A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for purification of refractory metal nitrides
Assignee: US Borax Inc
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Filing: 1970-12-09
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Granted: 1973-02-27
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Expires: 1990-12-09
Abstract
Abstract Carbon is removed from refractory metal nitrides, such as aluminum nitride, by heating the impure nitride with boric oxide in an atmosphere of nitrogen at a temperature of about 1,200 *2050* C. Boron nitride is formed and provides a valuable mixture of boron nitride and refractory metal nitride.
Inventors
- 👤 C Morgan
- 👤 O Young
- 👤 E Molesey
- 👤 S Arber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:13
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/58007; C04B35/58014; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C01B21/0648; C01B21/072; C01B21/0726; C01B21/0728; C01B21/076; C01B21/0768; C04B35/58028; C04B35/581; C04B35/583; C04B35/622; C04B35/626; C04B35/63; C04B35/632
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
22 words
The process according to claim 1 in which said impure aluminum nitride contains up to about 30 percent by weight of carbon.
Claim 2
Dependent Claim
37 words
The process according to claim 1 in which the boric oxide is present in an amount sufficient to react with all the carbon present according to the equation B2O3 + 3C + N2 -> 2BN + 3CO.
Claim 3
Dependent Claim
19 words
The process according to claim 1 in which said boric oxide is derived from boric acid during the reaction.
Claim 4
Dependent Claim
62 words
The process for removing carbon from impure aluminum nitride containing up to about 30 percent by weight of carbon which comprises heating said impure aluminum nitride with boric oxide in the presence of nitrogen at a temperature of from about 1, 200* to 2,050*C., thereby converting said boric oxide to boron nitride and providing a mixture of nitrides of aluminum and boron.
Claim 5
Dependent Claim
20 words
The process according to claim 5 in which said aluminum nitride contains alumina which is carbothermically reduced to aluminum nitride.
Claim 6
Dependent Claim
19 words
The process according to claim 5 in which said boric oxide is derived from boric acid during the reaction.
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) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |