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US 2009/0211514 A1Published application
Single crystal conversion process
AssigneeLehigh University
InventorsShen J. Dillon, Martin P. Harmer
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AssigneeLehigh University
InventorsShen J. Dillon, Martin P. Harmer
Estimating the term…
A solid state method for converting polycrystalline alumina components to single crystal or sapphire. The single crystal conversion method includes sintering a pre-fired polycrystalline alumina component doped with a magnesia sintering aid in an atmosphere containing a gas mixture of hydrogen and an inert gas, such as nitrogen in one embodiment. A sintering temperature is selected that preferably depends on the percentage of hydrogen selected. The component is held at the sintering temperature for a time sufficient to convert the polycrystalline component into a component formed of a single crystal. In one embodiment, the sintering temperature may be between at least about 1600° C. and less than 2050° C., and the amount of hydrogen in the sintering atmosphere may be between about 4% to about 10%. The method forms a wetting type intergranular film associated with the nucleation and growth of a single abnormal grain in the polycrystalline alumina component.
A solid state method for converting a polycrystalline alumina component into a single crystal component comprising:
A solid state method for converting a polycrystalline alumina component into a single crystal component comprising:
A solid state method for preparing an alumina single crystal component from polycrystalline alumina comprising:
Dependencies are inferred from the claim text.