US4533647A
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Ceramic compositions
Assignee: BOARD OF REGENTS ACTING FOR AND ON BEHALF OF UNIVERSITY OF MICHIGAN A MI CORP
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Filing: 1983-10-27
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Granted: 1985-08-06
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Expires: 2003-10-27
Abstract
Abstract Novel transformation toughened ceramic compositions comprising finely divided ZrO2-HfO2 solid solution particles dispersed in a Al2O3-Cr2O3 (alumina) or 3Al2O3.2SiO2-3Cr2O3.2SiO2 (mullite) solid solution matrix phase. It is found that increased hardness and modulus associated with higher relative Cr2O3 content (e.g. 20 mole %) in the matrix phase and increased fracture toughness associated with higher relative HfO2 content (e.g. 10 to 20 mole %) in the disperse phase represent viable and improved ceramic compositions. Such transformation toughened ceramic compositions are considered useful in superhot light diesel engine applications, high temperature gas turbines and ultrahigh temperature ceramic heat exchangers.
Inventors
- 👤 Tseng-Ying Tien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:30
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; C04B35/16; C04B35/18; C04B35/185; F; F02; F02B; F02B3/00; F02B3/06
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
88 words
A ceramic composition comprising: (a) a matrix phase selected from the group consisting of solid solutions characterized by the formula Al 2 O 3 .xCr 2 O 3 and the formula 3Al 2 O 3 .2SiO 2 +x[3Cr 2 O 3 .2SiO 2 ] where x is the relative mole fraction of Cr 2 O 3 or 3Cr 2 O 3 .2SiO 2 ; and (b) a dispersed phase characterized by the formula ZrO 2 .yHfO 2 where y is the relative mole fraction of HfO 2 .
Claim 2
Dependent Claim
88 words
A ceramic composition comprising: (a) a matrix phase selected from the group consisting of solid solutions characterized by the formula Al 2 O 3 .xCr 2 O 3 and the formula 3Al 2 O 3 .2SiO 2 +x[3Cr 2 O 3 .2SiO 2 ] where x is the relative mole fraction of Cr 2 O 3 or 3Cr 2 O 3 .2SiO 2 ; and (b) a dispersed phase characterized by the formula ZrO 2 .yHfO 2 where y is the relative mole fraction of HfO 2 .
Claim 3
Dependent Claim
24 words
A ceramic composition of claim 1 wherein x is from about 0.1 to about 0.5 and y is from about 0.02 to about 0.3.
Claim 4
Dependent Claim
28 words
A ceramic composition of claim 2 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 5
Dependent Claim
20 words
A ceramic composition of claim 1 wherein said matrix phase is Al 2 O 3 .xCr 2 O 3 .
Claim 6
Dependent Claim
24 words
A ceramic composition of claim 4 wherein x is from about 0.1 to about 0.5 and y is from about 0.02 to about 0.3.
Claim 7
Dependent Claim
28 words
A ceramic composition of claim 5 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 8
Dependent Claim
22 words
A ceramic compositon of claim 4 wherein x is from about 0.12 to about 0.2 and y is at least about 0.2.
Claim 9
Dependent Claim
28 words
A ceramic composition of claim 7 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 10
Dependent Claim
28 words
A ceramic composition of claim 4 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 11
Dependent Claim
24 words
A ceramic composition of claim 1 wherein said matrix phase is 3Al 2 O 3 .2SiO 2 +x[3Cr 2 O 3 .2SiO 2 ].
Claim 12
Dependent Claim
23 words
A ceramic composition of claim 10 wherein x is from about 0.1 to about 0.5 and y is from about 0.02 to 0.3.
Claim 13
Dependent Claim
28 words
A ceramic composition of claim 11 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 14
Dependent Claim
28 words
A ceramic composition of claim 10 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 15
Dependent Claim
28 words
A ceramic composition of claim 1 wherein said matrix phase is present in about 85 volume percent and said dispersed phase is present in about 15 volume percent.
Claim 16
Dependent Claim
40 words
A ceramic composition comprising: (a) a continuous matrix phase of Al 2 O 3 -Cr 2 O 3 solid solution; and (b) a dispersed phase within said continuous matrix phase of finely divided ZrO 2 -HfO 2 solid solution particles.
Claim 17
Dependent Claim
40 words
A ceramic composition comprising: (a) a continuous matrix phase of Al 2 O 3 -Cr 2 O 3 solid solution; and (b) a dispersed phase within said continuous matrix phase of finely divided ZrO 2 -HfO 2 solid solution particles.
Claim 18
Dependent Claim
45 words
A ceramic composition comprising: (a) a continuous matrix phase of 3Al 2 O 3 .2SiO 2 -3Cr 2 O 3 .2SiO 2 solid solution; and (b) a disperse phase within said continuous matrix phase of a finely divided ZrO 2 -HfO 2 solid solution particles.
Claim 19
Dependent Claim
45 words
A ceramic composition comprising: (a) a continuous matrix phase of 3Al 2 O 3 .2SiO 2 -3Cr 2 O 3 .2SiO 2 solid solution; and (b) a disperse phase within said continuous matrix phase of a finely divided ZrO 2 -HfO 2 solid solution particles.
Claim 20
Dependent Claim
22 words
A ceramic composition comprising finely dispersed zironcium dioxide/hafnium dioxide solid solution particles in a matrix phase of aluminum oxide/chromium oxide solid solution.
Claim 21
Dependent Claim
22 words
A ceramic composition comprising finely dispersed zironcium dioxide/hafnium dioxide solid solution particles in a matrix phase of aluminum oxide/chromium oxide solid solution.
Claim 22
Dependent Claim
22 words
A ceramic composition comprising finely dispersed zirconium dioxide/hafnium dioxide solid solution particles in a matrix phase of aluminum mullite/chromium mullite solid solution.
Claim 23
Dependent Claim
22 words
A ceramic composition comprising finely dispersed zirconium dioxide/hafnium dioxide solid solution particles in a matrix phase of aluminum mullite/chromium mullite solid solution.
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) | 1988-08-05 | 1989-02-04 | 1989-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-05 | 1993-02-04 | 1993-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-05 | 1997-02-04 | 1997-08-06 | $7700.00 | Window Closed / Lapsed |