Patent US4960735A successfully refreshed from Google Patents.
US4960735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina-zirconia-silicon carbide-magnesia ceramics
Assignee: Kennametal PC Inc
•
Filing: 1988-11-03
•
Granted: 1990-10-02
•
Expires: 2008-11-03
Abstract
Abstract An alumina based ceramic composition is provided containing (in volume percent, v/o): about 1.5 to 37.5 whiskers; about 5 to 17.5 zirconia; residue of a magnesium oxide addition added in an amount of about 0.03 to 3 v/o; and an alumina based matrix in which the silicon carbide whiskers, zirconia and residue of magnesium oxide are substantially homogeneously distributed. At least 2 v/o of the alumina based ceramic composition is tetragonal zirconia.
Inventors
- 👤 Pankaj K. Mehrotra
- 👤 Elizabeth R. Billman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:06
CPC Classifications
B; B23; B23B; B23B27/00; B23B27/14; B23B27/148; B24; B24D; B24D3/00; B24D3/02; C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; C04B35/622; C04B35/64; C04B35/645; C04B35/71; C04B35/78; C04B35/80; B23B2228/00; B23B2228/61
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
99 words
An alumina based ceramic composition consisting essentially of: about 1.5 to 32.5 v/o of carbide whiskers selected from the group consisting of silicon carbide whiskers, titanium carbide whiskers, alone or in combination; about 5 to 17.5 v/o zirconia; a residue of a magnesia addition added in the amount of about 0.03 to 3 v/o; alumina forming essentially the remainder of said composition; wherein said whiskers, said zirconia and said residue of said magnesia addition are substantially homogeneously dispersed in a matrix formed of said alumina; and wherein at least about 2.0 v/o of said ceramic composition is tetragonal zirconia.
Claim 2
Dependent Claim
99 words
An alumina based ceramic composition consisting essentially of: about 1.5 to 32.5 v/o of carbide whiskers selected from the group consisting of silicon carbide whiskers, titanium carbide whiskers, alone or in combination; about 5 to 17.5 v/o zirconia; a residue of a magnesia addition added in the amount of about 0.03 to 3 v/o; alumina forming essentially the remainder of said composition; wherein said whiskers, said zirconia and said residue of said magnesia addition are substantially homogeneously dispersed in a matrix formed of said alumina; and wherein at least about 2.0 v/o of said ceramic composition is tetragonal zirconia.
Claim 3
Dependent Claim
21 words
The alumina based ceramic composition according to claim 1 wherein at least about 4.0 v/o of said composition is tetragonal zirconia.
Claim 4
Dependent Claim
20 words
The alumina based ceramic composition according to claim 1 wherein at least 6 v/o of said composition is tetragonal zirconia.
Claim 5
Dependent Claim
25 words
The alumina based ceramic composition according to claim 1 wherein about 0.03 to 2 v/o of said composition is said residue of said magnesia addition.
Claim 6
Dependent Claim
25 words
The alumina based ceramic composition according to claim 1 wherein about 0.04 to 1.0 v/o of said residue of said composition is said magnesia addition.
Claim 7
Dependent Claim
20 words
The alumina based ceramic composition according to claim 1 wherein about 7.5 to 17.5 v/o of said composition is zirconia.
Claim 8
Dependent Claim
19 words
The alumina based ceramic composition according to claim 1 wherein 10.0 to 15.0 v/o of said composition is zirconia.
Claim 9
Dependent Claim
22 words
The alumina based ceramic composition according to claim 1 wherein said zirconia has an average particle size of less than 2 microns.
Claim 10
Dependent Claim
25 words
The alumina based ceramic composition according to claim 1 wherein said zirconia has an average particle size of less than or equal to one micron.
Claim 11
Dependent Claim
87 words
An alumina based ceramic composition consisting of about 1.5-32.5 v/o whiskers selected from the group consisting of silicon carbide whiskers and titanium carbide whiskers, alone or in combination, about 5 to 17.5 v/o ZrO 2 , a residue of a magnesia addition added in an amount of about 0.03 to 3 v/o, an alumina matrix wherein said whiskers, said zirconia and said residue of said magnesium oxide addition are substantially homogeneously distributed, and wherein tetragonal zirconia forms at least 2 v/o of said alumina based ceramic composition.
Claim 12
Dependent Claim
87 words
An alumina based ceramic composition consisting of about 1.5-32.5 v/o whiskers selected from the group consisting of silicon carbide whiskers and titanium carbide whiskers, alone or in combination, about 5 to 17.5 v/o ZrO 2 , a residue of a magnesia addition added in an amount of about 0.03 to 3 v/o, an alumina matrix wherein said whiskers, said zirconia and said residue of said magnesium oxide addition are substantially homogeneously distributed, and wherein tetragonal zirconia forms at least 2 v/o of said alumina based ceramic composition.
Claim 13
Dependent Claim
20 words
The alumina based ceramic composition according to claim 10 wherein at least 4 v/o of said composition is tetragonal zirconia.
Claim 14
Dependent Claim
20 words
The alumina based ceramic composition according to claim 10 wherein at least 6 v/o of said composition is tetragonal zirconia.
Claim 15
Dependent Claim
20 words
The alumina based ceramic composition according to claim 10 wherein at least 8 v/o of said composition is tetragonal zirconia.
Claim 16
Dependent Claim
22 words
The alumina based ceramic composition according to claim 10 wherein said zirconia has an average particle size no greater than 5 μm.
Claim 17
Dependent Claim
22 words
The alumina based ceramic composition according to claim 10 wherein said zirconia has an average particle size of less than 2 μm.
Claim 18
Dependent Claim
139 words
An article of manufacture comprising an alumina based ceramic composition having a K IC (E&C) toughness of at least about 5 MPam 1/2 , a Rockwell A hardness of at least 93; and a density of at least 98 percent of theoretical; said alumina based ceramic composition consisting essentially of: said alumina based ceramic composition consisting essentially of: about 1.5 to 32.5 v/o of carbide whiskers selected from the group consisting of silicon carbide whiskers, titanium carbide whiskers, alone or in combination; about 5 to 17.5 v/o zirconia; a residue of a magnesia addition added in the amount of about 0.03 to 3 v/o; an alumina matrix wherein said whiskers, said zirconia and said residue of said magnesium oxide addition are substantially homogeneously distributed, and wherein tetragonal zirconia forms at least 2.0 v/o of said alumina based ceramic composition.
Claim 19
Dependent Claim
139 words
An article of manufacture comprising an alumina based ceramic composition having a K IC (E&C) toughness of at least about 5 MPam 1/2 , a Rockwell A hardness of at least 93; and a density of at least 98 percent of theoretical; said alumina based ceramic composition consisting essentially of: said alumina based ceramic composition consisting essentially of: about 1.5 to 32.5 v/o of carbide whiskers selected from the group consisting of silicon carbide whiskers, titanium carbide whiskers, alone or in combination; about 5 to 17.5 v/o zirconia; a residue of a magnesia addition added in the amount of about 0.03 to 3 v/o; an alumina matrix wherein said whiskers, said zirconia and said residue of said magnesium oxide addition are substantially homogeneously distributed, and wherein tetragonal zirconia forms at least 2.0 v/o of said alumina based ceramic composition.
Claim 20
Dependent Claim
19 words
The article of manufacture according to claim 16 wherein at least 4 v/o of said composition is tetragonal zirconia.
Claim 21
Dependent Claim
19 words
The article of manufacture according to claim 16 wherein at least 6 v/o of said composition is tetragonal zirconia.
Claim 22
Dependent Claim
19 words
The article of manufacture according to claim 16 wherein at least 8 v/o of said composition is tetragonal zirconia.
Claim 23
Dependent Claim
21 words
The article of manufacture according to claim 16 wherein said zirconia has an average particle size no greater than 5 μm.
Claim 24
Dependent Claim
21 words
The article of manufacture according to claim 16 wherein said zirconia has an average particle size of less than 2 μm.
References Cited (Backward Citations)
US4419311A
Cited
US4298385A
Cited
US4218253A
Cited
US4421861A
Cited
US4292049A
Cited
US4331048A
Cited
US4366254A
Cited
US4316964A
Cited
US4506024A
Cited
US4507224A
Cited
US4543343A
Cited
US4745091A
Cited
US4543345A
Cited
WO1986005480A1
Cited
EP0194811A2
Cited
EP0202504A2
Cited
US4767727A
Cited
US4746635B1
Cited
US4746635A
Cited
EP0208910B1
Cited
US4789277A
Cited
US4789277B1
Cited
JPS62265182A
Cited
US4657877A
Cited
EP0252046A2
Cited
JPS6330378A
Cited
US4749667A
Cited
US4867761A
Cited
US4852999A
Cited
US4849381A
Cited
US4801510A
Cited
US4820663A
Cited
US4770673A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-01 | 1994-04-02 | 1994-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-01 | 1998-04-02 | 1998-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-01 | 2002-04-02 | 2002-10-02 | $7700.00 | Window Closed / Lapsed |