Patent US4107276A successfully refreshed from Google Patents.
US4107276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of hexagonal boron nitride
Assignee: Elektroschmelzwerk Kempten GmbH
•
Filing: 1977-06-20
•
Granted: 1978-08-15
•
Expires: 1997-06-20
Abstract
Abstract Process for the manufacture of hexagonal boron nitride which comprises causing a starting material containing an alkali metal boride or an alkaline earth metal boride, preferably a hexa- or dodecaboride, to react with nitrogen at temperatures of at least 900° C and, if desired, up to 2500° C, in the presence of impurities or additives of other boron compounds or compounds of the alkaline earth metals or of carbon compounds. Boron nitride has many uses in various fields, among them, electronics and crucible melting for most non-metallic melts.
Inventors
- 👤 Karl Alex Schwetz
- 👤 George Vogt
- 👤 Alfred Lipp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:21
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
A process for the manufacture of hexagonal boron nitride which comprises, reacting a starting material selected from the group consisting of an alkali metal hexaboride, an alkali metal dodecaboride, an alkaline earth metal hexaboride and an alkaline earth metal dodecaboride with a grain size having a minimum BET surface of 1 m 2 /g, with nitrogen at a temperature of at least about 900° C and a nitriding gas pressure of at least 1 bar, in the presence of at least one additive in the amount of at least 2% by weight, selected from the group consisting of B 2 O 3 , boric acid, boron carbide, an alkaline earth metal borate, carbon and iron.
Claim 2
Dependent Claim
115 words
A process for the manufacture of hexagonal boron nitride which comprises, reacting a starting material selected from the group consisting of an alkali metal hexaboride, an alkali metal dodecaboride, an alkaline earth metal hexaboride and an alkaline earth metal dodecaboride with a grain size having a minimum BET surface of 1 m 2 /g, with nitrogen at a temperature of at least about 900° C and a nitriding gas pressure of at least 1 bar, in the presence of at least one additive in the amount of at least 2% by weight, selected from the group consisting of B 2 O 3 , boric acid, boron carbide, an alkaline earth metal borate, carbon and iron.
Claim 3
Dependent Claim
13 words
The process according to claim 1, wherein the starting boride is calcium hexaboride.
Claim 4
Dependent Claim
33 words
The process according to claim 1, wherein the starting boride is calcium hexaboride and the additive is selected from the group consisting of boron trioxide, boric acid, a calcium borate and carbon black.
Claim 5
Dependent Claim
35 words
The process according to claim 1, wherein the additive is selected from the group consisting of boron trioxide, boric acid, and an alkaline earth metal borate in an amount not larger than 40% by weight.
Claim 6
Dependent Claim
21 words
The process according to claim 1, wherein the carbon-containing additive is present in an amount not larger than 20% by weight.
Claim 7
Dependent Claim
23 words
The process according to claim 1, wherein the nitridation is carried out above about 900° C under a nitrogen pressure of 100 bar.
Claim 8
Dependent Claim
25 words
The process according to claim 1, wherein the reaction is carried out at a temperature of at least about 1400° C in a nitrogen current.
Claim 9
Dependent Claim
21 words
The process according to claim 7, wherein the reaction is carried out at a temperature of from 1600° to 2000° C.
Claim 10
Dependent Claim
30 words
The process according to claim 1, wherein a gas mixture comprising nitrogen is used as the source of the nitrogen, the amount of nitrogen being at least 90% by volume.
Claim 11
Dependent Claim
18 words
The process according to claim 1, wherein technical grade nitrogen is used as the source of the nitrogen.
Claim 12
Dependent Claim
22 words
The process according to claim 1, wherein the starting material has a specific surface area of at least 5 m 2 /g.
Claim 13
Dependent Claim
22 words
The process according to claim 11, wherein the starting material has a specific surface area of at least 10 m 2 /g.
Claim 14
Dependent Claim
20 words
The process according to claim 7, wherein the starting material of submicron powder is made into porous granules before nitridation.
Claim 15
Dependent Claim
24 words
The process according to claim 1, wherein reaction products other than the boron nitride are removed during the heating operation via the gas phase.
Claim 16
Dependent Claim
39 words
The process according to claim 14, wherein only a part of the reaction products other than the boron nitride are removed from the boron nitride via the gas phase and the remainder by dissolution in a dilute mineral acid.
References Cited (Backward Citations)
US3189412A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-08-14 | 1982-02-13 | 1982-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-08-14 | 1986-02-13 | 1986-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-08-14 | 1990-02-13 | 1990-08-15 | $7700.00 | Window Closed / Lapsed |