Patent US4071371A successfully refreshed from Google Patents.
US4071371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High temperature ceramic material suitable for gas turbine applications and a process for producing same
Assignee: Ford Motor Co
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Filing: 1975-03-06
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Granted: 1978-01-31
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Expires: 1995-03-06
Abstract
Abstract A method of making improved SIALON ceramics without the need for hot pressing, is disclosed. A homogeneous slip is prepared from Si 3 N 4 , Al 2 O 3 and Y 2 O 3 in the presence of a suspension agent; Y 2 O 3 being present in at least 1% by weight (preferably between 1-25%) and Al 2 O 3 being present in the range 16-40% by weight (preferably 16-18%). The slip is cast and dehydrated. The cast shape is reaction sintered at about 1550°-1700° C (preferably 1600° C) for no less than 3 hours (preferably between 3-12 hours).
Inventors
- 👤 Morton E. Milberg
- 👤 Wayne M. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:44
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/597; Y; Y10; Y10T; Y10T407/00; Y10T407/27
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
112 words
A method of making ceramics, comprising: a. compact a desired powdered shape from a mixture of 99.9% pure Si 3 N 4 powder, Al 2 O 3 powder, and Y 2 O 3 powder, said Y 2 O 3 being present in said mixture at about essentially a 3% additive by weight and said Al 2 O 3 being present in an amount at about essentially 16% by weight b. with the absence of pressure, heat said shape to a temperature between 1550°-1700° C and hold at said temperature for a period of time at about essentially 12 hours, the resulting ceramic exhibiting a transverse rupture strength of at least 80,000 psi.
Claim 2
Independent Claim
112 words
A method of making ceramics, comprising: a. compact a desired powdered shape from a mixture of 99.9% pure Si 3 N 4 powder, Al 2 O 3 powder, and Y 2 O 3 powder, said Y 2 O 3 being present in said mixture at about essentially a 3% additive by weight and said Al 2 O 3 being present in an amount at about essentially 16% by weight b. with the absence of pressure, heat said shape to a temperature between 1550°-1700° C and hold at said temperature for a period of time at about essentially 12 hours, the resulting ceramic exhibiting a transverse rupture strength of at least 80,000 psi.
Claim 3
Independent Claim
115 words
A method of making ceramics, comprising: a. compact a desired powdered shape from a mixture of Si 3 N 4 powder, Al 2 O 3 powder, and Y 2 O 3 powder, said Y 2 O 3 being present in said mixture as about essentially a 3% additive by weight and said Al 2 O 3 being present in an amount essentially about 16% by weight, b. With the absence of pressure, heat said shape to a temperature between 1550°-1700° C and hold at said temperature for a period of time between 3-12 hours, said resulting ceramic exhibiting substantially a single phase and having a room temperature transverse rupture strength of at least 45,000 psi.
Claim 4
Independent Claim
115 words
A method of making ceramics, comprising: a. compact a desired powdered shape from a mixture of Si 3 N 4 powder, Al 2 O 3 powder, and Y 2 O 3 powder, said Y 2 O 3 being present in said mixture as about essentially a 3% additive by weight and said Al 2 O 3 being present in an amount essentially about 16% by weight, b. With the absence of pressure, heat said shape to a temperature between 1550°-1700° C and hold at said temperature for a period of time between 3-12 hours, said resulting ceramic exhibiting substantially a single phase and having a room temperature transverse rupture strength of at least 45,000 psi.
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) | 1981-01-30 | 1981-08-01 | 1982-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-30 | 1985-08-01 | 1986-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-30 | 1989-08-01 | 1990-01-31 | $7700.00 | Window Closed / Lapsed |