High-strength magnesia partially stabilized zirconia
AssigneeCarpenter Advanced Ceramics, Inc.
InventorsMartin D. Stuart, Wilson H. Ta
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Abstract
A high strength ceramic body and a method of making same are disclosed. The ceramic body is formed of ceramic composition containing 2.8-5.0% by weight MgO, an effective amount of grain growth inhibiting material, and the balance being essentially zirconia. The crystalline microstructure of the ceramic body comprises grains of cubic zirconia having an average grain size of less than about 30 microns in major dimension, 0.1-8.7% by volume of discrete particles of the grain growth inhibiting material, and precipitates of tetragonal zirconia having a substantially ellipsoidal shape with a long dimension of about 0.1-0.4 microns.
Claims17
A Mg-PSZ ceramic body formed from a ceramic powder composition consisting essentially of about 2.8-5.0% by weight MgO, an effective amount of a grain growth inhibiting additive, not more than about 0.3 mole % of yttria, ceria, other rare earth oxide, or strontia, and the balance being essentially zirconia, wherein said ceramic body has a crystalline microstructure comprising grains of cubic zirconia having an average grain size of less than about 30 microns in major dimension, discrete precipitates of tetragonal zirconia within the grains of cubic zirconia, and about 0.1-8.7% by volume of discrete particles of a grain growth inhibiting material which is or is formed from the grain growth inhibiting additive.
A ceramic body formed from a powder mixture consisting essentially of about 2.8-5.0% by weight magnesia, about 0.05-4.0% by weight alumina, not more than about 0.3 mole % yttria, ceria, other rare earth oxide, or strontia, and the balance essentially zirconia, wherein the ceramic body has a crystalline microstructure comprising:
- grains of cubic zirconia having an average grain size of less than about 30 microns in major dimension;
- 1-8.7% by volume of particles of magnesium aluminate spinel residing at the boundaries of the cubic zirconia grains and having an average size of less than about 5 microns in major dimension;
- and
- precipitates of tetragonal zirconia formed within the grains of cubic zirconia, said tetragonal zirconia precipitates having a substantially ellipsoidal shape with a long dimension of about 0.1-0.4 microns.
Dependencies are inferred from the claim text.