US4409193A
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Process for preparing cubic boron nitride
Assignee: National Institute for Materials Science
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Filing: 1982-03-03
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Granted: 1983-10-11
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Expires: 2002-03-03
Abstract
Abstract A process for preparing cubic boron nitride comprises heating hexagonal boron nitride and magnesium boron nitride at a temperature of at least 1350 DEG C. under a pressure at which the cubic boron nitride is thermodynamically stable, whereby the cubic boron having high strength and high purity can readily be obtainable. Also disclosed is a process for the preparation of magnesium boron useful as a starting material for the above process. This process comprises mixing hexagonal boron nitride and magnesium nitride or metal magnesium in a molar ratio of hexagonal boron nitride/magnesium being at least 0.6, and heating the mixture thus obtained, at a temperature of from 950 DEG to 1250 DEG C. under atmospheric pressure in a non-oxidizing atmosphere, e.g. a nitrogen atmosphere.
Inventors
- 👤 Tadao Sato
- 👤 Tadashi Endo
- 👤 Osamu Fukunaga
- 👤 Minoru Iwata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:34
CPC Classifications
C; C01; C01B; C01B35/00; C01B35/08; C01B35/14; C01B35/146; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/583; C04B35/5831
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
59 words
A process for preparing cubic boron nitride which comprises heating hexagonal boron nitride and magnesium boron nitride at a temperature of at least 1350° C. under pressure at which the cubic boron nitride is thermodynamically stable, said magnesium boron nitride having lattice spacings obtained from the major x-ray diffraction lines thereof as designated in Table 2 of the specification.
Claim 2
Dependent Claim
59 words
A process for preparing cubic boron nitride which comprises heating hexagonal boron nitride and magnesium boron nitride at a temperature of at least 1350° C. under pressure at which the cubic boron nitride is thermodynamically stable, said magnesium boron nitride having lattice spacings obtained from the major x-ray diffraction lines thereof as designated in Table 2 of the specification.
Claim 3
Dependent Claim
29 words
The process as claimed in claim 1, in which said hexagonal boron nitride is in an amount of at least 15% by weight relative to the magnesium boron nitride.
Claim 4
Dependent Claim
21 words
The process as claimed in claim 1, in which the temperature is within a range of from 1400° to 1600° C.
Claim 5
Dependent Claim
19 words
The process as claimed in claim 1, 2 or 3, in which the pressure is 47,000 atm or higher.
Claim 6
Dependent Claim
27 words
The process as claimed in claim 1, 2 or 3, in which the hexagonal boron nitride has an oxygen content of not more than 2.0% by weight.
Claim 7
Dependent Claim
53 words
A process for preparing magnesium boron nitride which comprises mixing hexagonal boron nitride and magnesium nitride or metal magnesium in a molar ratio of hexagonal boron nitride/magnesium being at least 0.6, and heating the mixture thus obtained, at a temperature of from 950° to 1250° C. under atmospheric pressure in a non-oxidizing atmosphere.
Claim 8
Dependent Claim
53 words
A process for preparing magnesium boron nitride which comprises mixing hexagonal boron nitride and magnesium nitride or metal magnesium in a molar ratio of hexagonal boron nitride/magnesium being at least 0.6, and heating the mixture thus obtained, at a temperature of from 950° to 1250° C. under atmospheric pressure in a non-oxidizing atmosphere.
Claim 9
Dependent Claim
21 words
The process as claimed in claim 6, in which said molar ratio is within a range of from 0.6 to 1.0.
Claim 10
Dependent Claim
21 words
The process as claimed in claim 6, in which the temperature is within a range of from 1100° to 1160° C.
Claim 11
Dependent Claim
19 words
The process as claimed in claim 6, 7 or 8, in which the non-oxidizing atmosphere is a nitrogen atmosphere.
Claim 12
Dependent Claim
91 words
A process for preparing cubic boron nitride which comprises: (a) preparing magnesium boron nitride by mixing hexagonal boron nitride and magnesium nitride or metal magnesium in a molar ratio of hexagonal boron nitride/magnesium of at least 0.6, and heating the mixture thus obtained at a temperature of from 950° to 1250° C. under atmospheric pressure in a non-oxidizing atmosphere, and (b) heating hexagonal boron nitride and said magnesium boron nitride from (a) at a temperature of at least 1350° C. under a pressure at which cubic boron nitride is thermodynamically stable.
Claim 13
Dependent Claim
91 words
A process for preparing cubic boron nitride which comprises: (a) preparing magnesium boron nitride by mixing hexagonal boron nitride and magnesium nitride or metal magnesium in a molar ratio of hexagonal boron nitride/magnesium of at least 0.6, and heating the mixture thus obtained at a temperature of from 950° to 1250° C. under atmospheric pressure in a non-oxidizing atmosphere, and (b) heating hexagonal boron nitride and said magnesium boron nitride from (a) at a temperature of at least 1350° C. under a pressure at which cubic boron nitride is thermodynamically stable.
References Cited (Backward Citations)
CH506438A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |