US3830652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hot pressed, high strength silicon nitride
Assignee: United States Department of the Army
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Filing: 1973-06-28
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Granted: 1974-08-20
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Expires: 1993-06-28
Abstract
Abstract The fabrication of high strength, high density, silicon nitride by the addition of between 1.0 to 3.5 percent by weight of yttrium in the form of a compound to silicon nitride powder and pressing the material at temperatures of between 1,750* C. and 1,800* C. and at uniaxial pressures of between 6,000 and 7,000 psi.
Inventors
- 👤 G Gazza
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:44
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
26 words
A composition according to claim 1 in which the yttrium compound is a member of the group consisting of yttrium chloride, yttrium nitrate and yttrium oxide.
Claim 2
Dependent Claim
14 words
A composition according to claim 1 in which the yttrium compound is yttrium oxide.
Claim 3
Dependent Claim
27 words
A composition according to claim 3 in which the amount of yttrium oxide is about 1.25 to 4.45 weight percent of the weight of the silicon nitride.
Claim 4
Independent Claim
49 words
A method of enhancing the strength of a silicon nitride monolith which comprises adding a powdered yttrium compound to powdered silicon nitride, the weight of yttrium in the yttrium compound being abOut 1.0 to 3.5 percent of the weight of the silicon nitride, and sintering the composition by hot-pressing.
Claim 5
Dependent Claim
14 words
A method according to claim 5 in which the yttrium compound is yttrium oxide.
Claim 6
Dependent Claim
24 words
A method according to claim 6 in which the amount of yttrium oxide is about 1.25 to 4.45 weight percent of the silicon nitride.
Claim 7
Dependent Claim
31 words
A method in accordance with claim 7 in which the sintering is carried out at temperatures between 1,750* C. and 1,800* C. and at pressures between 6,000 psi and 7,000 psi.
Claim 8
Dependent Claim
35 words
A method in accordance with claim 5 in which the sintering is carried out at a temperature of about 1,750* C. to 1,800* C. and at a pressure of about 6,000 psi to 7,000 psi.
Claim 9
Dependent Claim
35 words
A method in accordance with claim 9 in which the sintering is carried out at a temperature of about 1,750* C. to 1,800* C. and at a pressure of about 6,000 psi to 7,000 psi.
Claim 10
Dependent Claim
27 words
A method in accordance with claim 5 in which the yttrium compound is a member of the group consisting of yttrium chloride, yttrium nitrate and yttrium oxide.
References Cited (Backward Citations)
US3108887A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-19 | 1978-02-18 | 1978-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-19 | 1982-02-18 | 1982-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-19 | 1986-02-18 | 1986-08-20 | $7700.00 | Window Closed / Lapsed |