Abstract: Polycrystalline alumina and methods for manufacturing polycrystalline alumina exhibiting improved transmission in the infrared region. In one embodiment, polycrystalline alumina articles are formed by providing a powder of substantially alpha phase alumina having a grain size of up to about 1 ?m, dispersing the powder in a liquid to form a slurry comprising powdered solids and liquid, removing excess of the liquid from the slurry to form a body, heating the body to provide a densified body, hot isostatically pressing the densified body under conditions to provide an article having a density of at least about 99.9% of theoretical density, and optionally annealing the article, wherein one or more of the annealing or heating are performed in an inert, dry gas.

Abstract: A method and device for making integrally formed one-piece molded parts is provided, where the molded parts are to contain a void within their volume. An exemplary such molded part is an arc tube for a discharge lamp. A wax core is first molded onto a core pin wire in the shape of the desired void, the discharge chamber in the case of an arc tube. Then the part is molded over the wax core to provide an integrally formed one-piece part having the appropriately dimensioned void volume therein defined by the wax core. After the part has been hardened around the wax core, the core is removed by conventional means. The holes through the finished molded part left after the core pin wire is removed can be filled in, or in the case of an arc tube they are useful as passageways to accommodate electrodes therethrough.

Abstract: This invention pertains to product and process. The product is a transparent product of a density in excess 99.5% comprising spinel and having uniform mechanical properties. The process pertains to fabrication of a transparent spinel product comprising the steps of dissolving a sintering aid in water to form a neutral sintering aid solution, adding a suitable additive to the sintering aid solution, applying the sintering aid solution to spinel particles to form a spinel dispersion, sub-dividing or atomizing the spinel dispersion to form droplets comprising one or more spinel particles coated with the final spinel solution, drying the droplets to form dried coated particles comprising one or more spinel particles coated with a dried layer of the sintering aid, and densifying the dried coated particles to form a transparent spinel product having, uniform optical and mechanical properties in absence of grains of exaggerated size.

Abstract: A synthetic fire opal and a process for its preparation. Synthetic fire opals have similar physical and chemical properties as natural fire opals. Synthetic fire opals are colored, hard, and transparent. The process of preparation of synthetic fire opal includes; mixing TEOS with absolute ethanol (99.9%), distilled water, concentrated nitric acid, and an inorganic salt to form a clear sol, storing the clear sol to obtain a gel, drying the gel and sintering the dried gel to obtain a synthetic fire opal.

Abstract: A ceramic material powder for a translucent ceramic is molded with a binder, and the resulting green compact is embedded in a ceramic powder having the same composition with the ceramic material powder. After removing the binder, the green compact embedded in the ceramic powder is fired in an atmosphere having an oxygen concentration higher than that in the removal procedure of the binder and thereby yields a translucent ceramic represented by Formula I: Ba{(SnuZr1-u)xMgyTaz}vOw, Formula II: Ba(ZrxMgyTaz)vOw or Formula III: Ba{(SnuZr1-u)x(ZntMg1-t)yNbz}vOw. The translucent ceramic has a refractive index of 1.9 or more and is paraelectric.

Abstract: A hard film for cutting tools which is composed of (Ti1?a?b?c?d, Ala, Crb, Sic, Bd)(C1?eNe) 0.5?a?0.8, 0.06?b, 0?c?0.1, 0?d?0.1, 0?c+d?0.1, a+b+c+d<1, 0.5?e?1 (where a, b, c, and d denote respectively the atomic ratios of Al, Cr, Si, and B, and e denotes the atomic ratio of N).

Abstract: A transparent scintillator material for rapid conversion of exciting radiation, such as x-rays, to scintillating radiation. The scintillator material has a cubic garnet host, and has praseodymium as an activator. The scintillator material may be a polycrystalline ceramic material. The polycrystalline ceramic is formed by sintering a powder formed by precipitation. The scintillator material may be integrated into computed tomography (CT) equipment or other x-ray imaging equipment. The scintillator material may also be integrated into a fast response x-ray detector system.

Abstract: A sintered, translucent ceramic article comprises alpha alumina and up to 0.050 wgt. percent magnesia and between 0.001 to 0.100 wgt. percent lutetium oxide. In a preferred embodiment, the lutetium oxide is at 0.050 wgt. percent and in a second preferred embodiment half the lutetium oxide is replaced by yttrium oxide. A method of making a translucent ceramic article comprises the steps of: forming an aqueous slurry to yield one of the composition described above; adding nitric acid to adjust the pH to 4.6; adding an aqueous binder and plasticizer in the amount of 2.5 solids wgt. percent; spray-drying the slurry; forming an article by wet-bag isopressing; prefiring said article in air at about 1325.degree. C. for about 2 hours; and sintering said air-fired article in hydrogen for about 3 hours at 1800.degree. C.