Transparent yttria ceramics and method for producing same
AssigneeGTE Laboratories Incorporated
InventorsWilliam H. Rhodes, F. Joseph Reid
Life of this patent
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Abstract
An article of manufacture is provided comprising a substantially transparent high density polycrystalline yttria-base body consisting essentially of yttria and from about 0.01 to 5 wt. % alumina. A method for preparing the transparent yttria doped with alumina is also provided comprising admixing alumina or a precursor thereof with yttria or a precursor thereof, drying the admixed powders, calcining the admixed powders and pressing the calcined powders into a desired shape and thereafter sintering the shaped powder for about 1/4 to six hours at a temperature above the eutectic temperature at a sufficiently low oxygen atmosphere to prevent oxidative contaminants.
Claims16
A process for preparing a substantially transparent, high density polycrystalline yttria-based body comprising the steps of:
- admixing alumina or a precursor thereof convertible by sintering to alumina, with yttria or a precursor thereof convertible by sintering to yttria to form a mixture, the alumina or precursor thereof being present in the mixture in an amount to provide between about 0.01 and 5 wt. % alumina upon subsequent sintering;
- drying the resulting powder;
- calcining the dried powder at 1000.degree. C. in air;
- pressing the calcined powder into a given shape;
- and sintering the shaped powder for about 1/4 to six hours above the eutectic temperature in an atmosphere sufficiently low in oxygen to prevent oxidative contamination.
A process for preparing a substantially transparent, high density polycrystalline yttria-based body comprising the steps of:
- admixing alumina or a precursor thereof convertible by sintering to alumina, with yttria or a precursor thereof convertible by sintering to yttria to form a mixture, the alumina or precursor thereof being present in the mixture in an amount to provide between about 0.01 and 5 wt. % alumina upon subsequent sintering;
- drying the resulting powder;
- calcining the dried powder at 1000.degree. C. in air;
- pressing the calcined powder into a given shape;
- and
- sintering the shaped powder for from about 1 to 8 hours below 1920.degree. C., about 1/4 to 6 hours above 1920.degree. C. and about 1 to 2 hours at or about 1925.degree. C. in an atmosphere sufficiently low in oxygen to prevent oxidative contamination.
Dependencies are inferred from the claim text.