Abstract: The invention is directed to a method of producing polycrystaline silicon metal from a silicon halide plasma source. The silicon halide is split into silicon and halide ions in an inductively coupled plasma and silicon ions are then condensed to form molten silicon metal that can be vacuum cast into polysilicon ingots. The halide ions are separated and recycled into silicon halide gas over a silicon dioxide bed. In this way, high grade polysilicon is produced without a metallurgical grade silicon precursor and the process these processes consumes the byproducts in a continuous manner madding it less expensive than traditional methods of producing polysilicon and more environmentally friendly.

Abstract: The invention is directed to luminescent materials containing isotopically-enriched atomic elements and methods of making these luminescent materials. Individual embodiments of the invention include isotopically-enriched ZnO:Zn, ZnS:Cu:Cl, Zn2SiO4:Mn, Y2O2S:Eu, Gd2O2S:Tb and CaWO4 phosphors as well as methods of synthesizing these luminescent materials using isotopically-enriched starting materials.

Abstract: The invention is directed to a method of producing polycrystaline silicon metal from a silicon halide plasma source. The silicon halide is split into silicion and halide ions in an inductively coupled plasma and silicon ions are then condensed to form molten silicon metal that can be vacuum cast into polysilicon ingots. The halide ions are separated and recycled into silicon halide gas over a silicon dioxide bed. In this way, high grade polysilicon is produced without a metallurgical grade silicon precursor and the process these processes consumes the byproducts in a continuous manner madding it less expensive than traditional methods of producing polysilicon and more environmentally friendly.

Abstract: The invention is directed to luminescent materials containing isotopically-enriched atomic elements and methods of making these luminescent materials. Individual embodiments of the invention include isotopically-enriched ZnO:Zn, ZnS:Cu:Cl, Zn2SiO4:Mn, Y2O2S:Eu, Gd2O2S:Tb and CaWO4 phosphors as well as methods of synthesizing these luminescent materials using isotopically-enriched starting materials.

Abstract: The invention comprises a method of making self-supporting ceramic and ceramic composite structures by the oxidation reaction of a body of molten parent metal precursor with a vapor-phase oxidant to form an oxidation reaction product. This reaction or growth is continued to form a thick, self-supporting ceramic or ceramic composite body. The body is recovered and in a separate subsequent operation, at least a portion of a surface is coated with one or more materials in order to effect desired changes in the properties of the surface, e.g., hardness, corrosion resistance.

Abstract: This invention relates generally to a novel method of preparing self-supporting bodies, and to novel products made thereby. In its more specific aspects, this invention relates to a method of producing self-supporting bodies comprising one or more boron-containing compounds, e.g., a boride or a boride and a carbide, by reactive infiltration of a molten parent metal actinide into (1) a bed or mass containing boron carbide and, optionally, (2) at least one of a boron donor material (i.e., a boron-containing material) and a carbon donor material (i.e., a carbon-containing material), (3) a bed or mass comprising a mixture of a boron donor material and a carbon donor material and, optionally, (4) one or more inert fillers in any of the above masses, to form the body.

Abstract: This invention relates generally to a novel method of preparing self-supporting bodies, and to novel products made thereby. In its more specific aspects, this invention relates to a method of producing self-supporting bodies comprising one or more boron-containing compounds, e.g., a boride or a boride and a carbide, by reactive infiltration of a molten parent metal actinide into (1) a bed or mass containing boron carbide and, optionally, (2) at least one of a boron donor material (i.e., a boron-containing material) and a carbon donor material (i.e., a carbon-containing material), (3) a bed or mass comprising a mixture of a boron donor material and a carbon donor material and, optionally, (4) one or more inert fillers in any of the above masses, to form the body.

Abstract: A method of fabricating a seal between a ceramic and an alloy comprising the steps of prefiring the alloy in an atmosphere with a very low partial pressure of oxygen, firing the assembled alloy and ceramic in air, and gradually cooling the fired assembly to avoid the formation of thermal stress in the ceramic. The method forms a bond between the alloy and the ceramic capable of withstanding the environment of a pressurized water reactor and suitable for use in an electrical conductivity sensitive liquid level transducer.

Abstract: Phosphors having the general formula (A.sub.1.sub.-x RE.sub.x).sub.2 Hf.sub.2 O.sub.7 are disclosed wherein A is selected from the group consisting of yttrium, gadolium, lanthanum, scandium and lutetium; RE is selected from the group consisting of praseodymium, samarium, europium, terbium, dysprosium, holmium, erbium and thulium; and x is from about 0.001 to 0.10. The phosphors are prepared by dissolving an oxide of A and an oxide of RE in a mineral acid and dissolving HfOCl.sub.2 in water and combining the two solutions. A precipitating agent such as oxalic acid is added and the precipitate is washed, dried and fired to produce the phosphors.

Abstract: A phosphor composition having the general formula HfO.sub.2 :Yb with ytterbium being present in an amount of from 0.005 to 0.10 moles per mole of hafnium is disclosed. The phosphor can be prepared from the mixed oxides or from the oxalates, carbonates, or hydroxides by precipitating the latter from an aqueous solution. Firing takes place under a reducing atmosphere, preferably nitrogen, to reduce the ytterbium to the plus 2 ion. The phosphor is a bright green emitter under ultraviolet, x-radiation and cathode ray excitation.