Abstract: A process for forming a smooth, continuous coating of silicon carbide upon antalum carbide is disclosed, as are several useful manufacturers produced with the process. A tantalum carbide substrate may be formed directly upon metallic tantulum articles by disclosed means. The material formed with this process has been used to fabricate semiconducting devices including light emitting diodes and selective thermal radiators which can be operate at 1200 degrees C. The method is further useful for producing tantalum metal incandescent light filaments and corrosion resistant tantalum articles.

Abstract: A method of recovering intact at room temperature a layer of a first material, such as silicon carbide, produced by depositing it from the gas phase at a deposition temperature above room temperature on a substrate of a second material, such as silicon, having a different coefficient of thermal expansion than that of the first material. The substrate is separated from the layer prior to cooling, and then the separated layer is cooled to room temperature free of stresses otherwise present as a result of the different thermal expansions of the substrate and layer.

Abstract: The improvement of the electrolytic and additive methods of coloring alkali fluoride crystals comprising the step of selecting an alkali fluoride crystal having the impurities of between 0 and 5 ppmA of OH; between 0 and 50 ppmA of one or more alkaline earth cations, of which between 0 and 10 ppmA Mg.sup.++ and between 0 and 10 ppmA Ca.sup.++ ; between 0 and 50 ppmA of non-fluorine halide anions; between 0 and 10 ppmA of SiF.sub.6.sup.= ; between 0 and 30 ppmA of other ions; and the method of preparing these crystals which comprises converting the alkali fluoride to alkali hydrofluoride, crystallizing and vacuum drying the alkali hydrofluoride crystals, regenerating the alkali fluoride by expelling hydrogen fluoride, and crystallizing the alkali fluoride.

Abstract: A cubia, yttria stabilized halnia phosphor, doped with Ce.sup.3+, has been iscovered. The phosphor has a blue luminescence, peaking at about 4200 A, with a secondary peak in the 3800-4000 A region. The optimum composition is 3hfO.sub.2 :Y.sub.2 O.sub.3 :Ce.sup.3+ where the Ce.sup.3+ dopant ranges from 0.1-1.0 weight %.

Abstract: The improvement of the electrolytic and additive methods of coloring alkali fluoride crystals comprising the step of selecting an alkali fluoride crystal having the impurities of between 0 and 5 ppmA of OH; between 0 and 50 ppmA of one or more alkaline earth cations, of which between 0 and 10 ppmA Mg.sup.++ and between 0 and 10 ppmA Ca.sup.++ ; between 0 and 50 ppmA of non-fluorine halide anions; between 0 and 10 ppmA of SiF.sub.6.sup.= ; between 0 and 30 ppmA of other ions; and the method of preparing these crystals which comprises converting the alkali fluoride to alkali hydrofluoride, crystallizing and vacuum drying the alkali hydrofluoride crystals, regenerating the alkali fluoride by expelling hydrogen fluoride, and crystallizing the alkali fluoride.