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Patent US4804645A successfully refreshed from Google Patents.
US4804645A
Expired / Lapsed
US
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Ceramic material based on alumina and refractory hard constituents
Assignee: Sandvik AB
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Filing: 1987-03-27
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Granted: 1989-02-14
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Expires: 2007-03-27
Abstract
Abstract The invention relates to a sintered body of a ceramic composite material based on alumina, refractory hard phases and ZrO2, HfO2 and/or partially stabilized ZrO2 with a relative density of more than 98 %. The sintered body according to the invention has chromium integrated in amounts corresponding to in all 1-20 weight% and ZrO2, HfO2 and/or partially stabilized ZrO2 present as 2-16 weight% and these latter phases are present to more than 70 % in the tetragonal crystal modification. Furthermore, the refractory hard constituents are present as particles with a grain size of less than 10 mu m and/or as whiskers or fibers with a diameter of less than 5 mu m and a length/diameter ratio of >10 and/or as platelets with a diameter of 5 - 50 mu m and a thickness of 0.5 - 8 mu m.
Inventors
- 👤 Claes T. Ekstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:06
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; C04B35/71; C04B35/78; C04B35/80
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
147 words
A sintered body of a ceramic composite material comprising alumina, an amount sufficient to improve the fracture toughness of particles and/or whiskers or fibers of refractory hard constituents of one or more metals of the elements Group IVB, VB or VIB of the periodic system, said refractory hard constituent particle having a grain size less than 10 μm, said refractory hard constituent whisker or fiber having a diameter less than 5 μm and a length/diameter ratio of greater than 10, from 2-16 weight % of ZrO 2 , HfO 2 and/or partially stabilized ZrO 2 with more than 70% of said ZrO 2 , HfO 2 and/or partially stabilized ZrO 2 present in the tetragonal crystal modification, chromium present in amounts corresponding to a total of from 1-20 weight % as Cr 2 O 3 , and said sintered body having a relative density greater than 98%.
Claim 2
Dependent Claim
147 words
A sintered body of a ceramic composite material comprising alumina, an amount sufficient to improve the fracture toughness of particles and/or whiskers or fibers of refractory hard constituents of one or more metals of the elements Group IVB, VB or VIB of the periodic system, said refractory hard constituent particle having a grain size less than 10 μm, said refractory hard constituent whisker or fiber having a diameter less than 5 μm and a length/diameter ratio of greater than 10, from 2-16 weight % of ZrO 2 , HfO 2 and/or partially stabilized ZrO 2 with more than 70% of said ZrO 2 , HfO 2 and/or partially stabilized ZrO 2 present in the tetragonal crystal modification, chromium present in amounts corresponding to a total of from 1-20 weight % as Cr 2 O 3 , and said sintered body having a relative density greater than 98%.
Claim 3
Dependent Claim
28 words
Sintered body according to claim 1 in which the refractory hard constituent is one or more nitrides, carbides or borides of the elements titanium, zirconium, molybdenum or tungsten.
Claim 4
Dependent Claim
22 words
A sintered body according to claim 2 in which the refactory hard constituent is present in and out from 5-50 weight %.
Claim 5
Dependent Claim
23 words
A sintered body according to claim 3 in which the refractory hard constituent is present in the amount of from 10-40% by weight.
Claim 6
Dependent Claim
21 words
A sintered body according to claim 3 in which the refractory hard constituent is a carbide, nitride or boride of titanium.
Claim 7
Dependent Claim
15 words
A sintered body according to claim 3 in which the density is greater than 99%.
Claim 8
Dependent Claim
15 words
A sintered body according to claim 3 in which the chromium is added as chromia.
Claim 9
Dependent Claim
26 words
Sintered body according to claim 1 in which the refractory hard phases are present as whiskers of one or more of TiN, TiC, TiB 2 .
Claim 10
Dependent Claim
22 words
A sintered body according to claim 1 in which the whiskers or fibers have a diameter less than 2 μm in diameter.
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) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |