US4218253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sintered ceramic material of improved ductility
Assignee: Cerasiv GmbH Innovatives Keramik Engineering
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Filing: 1978-10-02
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Granted: 1980-08-19
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Expires: 1998-10-02
Abstract
Abstract The ductility of sintered bodies of alumina and like hard substances can be improved without loss in mechanical strength by uniformly distributed individual particles of tetragonal zirconia or hafnia in amounts of 1%-50% by volume if the dispersed particles have an average size of 0.05 to 2 μm.
Inventors
- 👤 Ulf Dworak
- 👤 Hans Olapinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:22
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/575; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; Y; Y10; Y10T; Y10T407/00; Y10T407/27
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
104 words
A densely sintered material consisting essentially of a matrix and individual particles of at least one oxide of the group consisting of zirconium oxide and hafnium oxide, said individual particles being uniformly distributed in said matrix and being present in said material in an amount of one to fifty percent by volume, said oxide being predominantly in the tetragonal crystal form, and the average size of said individual particles being between 0.05 and 2 μm, said matrix consisting essentially of at least one member of the group consisting of silicon carbide, titanium carbide, niobium carbide, tungsten carbide, silicon nitride, titanium nitride, and aluminum oxide.
Claim 2
Dependent Claim
104 words
A densely sintered material consisting essentially of a matrix and individual particles of at least one oxide of the group consisting of zirconium oxide and hafnium oxide, said individual particles being uniformly distributed in said matrix and being present in said material in an amount of one to fifty percent by volume, said oxide being predominantly in the tetragonal crystal form, and the average size of said individual particles being between 0.05 and 2 μm, said matrix consisting essentially of at least one member of the group consisting of silicon carbide, titanium carbide, niobium carbide, tungsten carbide, silicon nitride, titanium nitride, and aluminum oxide.
Claim 3
Dependent Claim
17 words
A material as set forth in claim 1, wherein said at least one member is aluminum oxide.
Claim 4
Dependent Claim
26 words
A material as set forth in claim 2, wherein said aluminum oxide contains 0.05% to 0.25% by weight magnesium oxide as a grain growth controlling agent.
Claim 5
Dependent Claim
26 words
A material as set forth in claim 2, wherein said material contains 2.5 to 20 percent by volume of said oxide in said tetragonal crystal form.
Claim 6
Dependent Claim
19 words
A material as set forth in claim 1 having a flexural breaking strength greater than 500±50 N/mm 2 .
Claim 7
Dependent Claim
22 words
A material as set forth in claim 1, wherein the average size of said individual particles is between 0.1 and 1.5 μm.
Claim 8
Dependent Claim
14 words
A material as set forth in claim 1, which is substantially free from microfissures.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |