US3811900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refractory article having high thermal shock resistance
Assignee: Lanteris Space LLC
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Filing: 1972-01-07
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Granted: 1974-05-21
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Expires: 1992-01-07
Abstract
Abstract Highly ordered boron nitride flakes having a greater surface dimension between about 0.003 inch and 0.030 inch and a thickness less than one-tenth of the greater surface dimension are mixed homogeneously with a refractory material and formed into a refractory article. The boron flakes intersect and arrest microcracks formed in the article by thermal shock or other stress producing conditions. Suitable highly ordered boron nitride flakes can be made by grinding pyrolytic boron nitride obtained by reacting a gaseous mixture of boron trichloride and ammonia.
Inventors
- 👤 W Fassell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:33
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/08; C04B35/10; C04B35/111; C04B35/71; C04B35/78; C04B35/80
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
23 words
The refractory article of claim 1 in which the boron nitride flakes have a thickness less than one-tenth of the greater surface dimension.
Claim 2
Dependent Claim
25 words
The refractory article of claim 2 in which the greater surface dimension of the boron nitride flakes is between about 0.003 inch and 0.030 inch.
Claim 3
Dependent Claim
18 words
The refractory article of claim 3 in which the boron nitride flakes are highly ordered pyrolytic boron nitride.
Claim 4
Dependent Claim
18 words
The refractory article of claim 4 comprising about 1 to 20 weight percent of said boron nitride flakes.
Claim 5
Dependent Claim
25 words
The refractory article of claim 1 in which the greater surface dimension of the boron nitride flakes is between about 0.003 inch and 0.030 inch.
Claim 6
Dependent Claim
18 words
The refractory article of claim 1 in which the boron nitride flakes are highly ordered pyrolytic boron nitride.
Claim 7
Dependent Claim
18 words
The refractory article of claim 1 comprising about one to twenty weight percent of said boron nitride flakes.
Claim 8
Dependent Claim
50 words
A process for producing a refractory article having high thermal shock resistance comprising preparing highly ordered boron nitride flakes having a greater surface dimension of at least 0.002 inch, mixing homogeneously said boron nitride flakes with a refractory material, and forming the mixture into the shape of the refractory article.
Claim 9
Dependent Claim
81 words
The process of claim 9 in which the step of preparing the boron nitride flakes comprises heating a gaseous mixture of boron trichloride and ammonia to at least 2,000*C. in the presence of a graphite substrate and depositing the resulting boron nitride on the graphite substrate, and the forming step comprises forming the mixture into the shape of the refractory article and hot pressing the article at a temperature of at least two thirds of the melting temperature of the mixture.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |