Abstract: Provided herein are methods and apparatus to remove unwanted elements in commercial powders, and particularly in commercial powders that include one or more of a crystalline ceramic oxide. The methods involve treating powders in reduced pressure atmosphere, such as a vacuum, with or without heating, for a period of time sufficient to remove impurities. Impurities and contaminants, including anionic species, are removed from the powders without any undesirable changes in the physical characteristics of the starting material, such as particle size and particle size distribution, surface area, and volume, for example. The resulting purified powder starting material can be consolidated without the need for any sintering aids such as LiF to produce nearly colorless, extremely transparent polycrystalline articles that approach identical properties and performance of single crystal spinels.

Abstract: Inorganic microporous metal oxide materials, such as aluminum-based microporous ceramic materials, useful for loop heat pipes, insulators, thermal management devices, catalyst supports, substrates, and filters, among others. An example method of manufacture includes heating a mixture of alumina (Al2O3) and aluminum carbonate (Al2(CO3)3) powders to a temperature of at least about 1400 degrees Celsius for a pre-selected time.

Abstract: 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.

Abstract: A method is disclosed for forming a single crystal relaxor based material, including the following steps: providing a seed single crystal plate, providing a first and second polycrystalline structure, bonding the top surface of the seed crystal plate to the outer surface of the first polycrystalline structure, bonding the bottom surface of the seed crystal plate to the outer surface of the second polycrystalline structure, and annealing the bonded structure.

Abstract: A process for superplastically forming and shaping a solid object including 123 superconductor, including preparing a solid object having grains of 123 superconductor that have an average grain size of less than 10 microns, and superplastically deforming the prepared solid object by heating the solid object to between 500.degree. and 1015.degree. C. while simultaneously applying to said solid object stress which is less than the fracture strength of the solid object, thereby producing a strain rate in the solid object. The solid object may be a composite including silver or gold.