Abstract: A radial flow turbine rotor comprises a trunconical shaft and a plurality of blades provided on the periphery of the shaft and inclined to the axis of the shaft. The shaft and the blades are integrally formed of ceramics. The profile of the cross section of each blade, taken along a line perpendicular to the axis of the shaft, is straight between the tip and base of the blade. The tip of each blade is 1.2 to 2.0 mm thick, and each blade grows thicker from the tip toward the base.

Abstract: An apparatus has a crucible for containing a GaAs raw material melt and a B.sub.2 O.sub.3 liquid encapsulating material therein, a heat generator arranged around the crucible so as to be coaxial therewith, and a heat insulator assembly arranged around the heat generator to surround the heat generator and the crucible for the purpose of manufacturing a compound semiconductor single crystal by pulling it from the raw material melt in the crucible by the LEC method. In the heat insulator assembly of the apparatus of the above construction, an upper heat insulator, arranged above the crucible and having at its center a circular hole for receiving the single crystal being pulled, comprises a plurality of radially divided sector-shaped split members. The split members are sintered bodies having aluminum nitride (AlN) as a major constituent.

Abstract: A sintered ceramic body is manufactured first by preparing a composition containing a binder and a ceramic powder having a particle size distribution given such that 0 to 1 weight % of ceramic particles with a particle size of less than 0.2 .mu.m, 0 to 2 weight % of ceramic particles with a particle size of 0.2 .mu.m to less than 0.5 .mu.m, 5 to 15 weight % of ceramic particles with a particle size of 0.5 .mu.m to less than 1.0 .mu.m, 5 to 15 weight % of ceramic particles with a particle size of 1.0 .mu.m to less than 1.5 .mu.m, 5 to 15 weight % of ceramic particles with a particle size of 1.5 .mu.m to less than 2.0 .mu.m, and 50 to 80 weight % of ceramic particles with a particle size of not less than 2.0 .mu.m. The prepared composition is then injection-molded into a predetermined shape. The binder is removed from the molded body, and the binder-free molded body is sintered.

Abstract: A method of manufacturing a radial flow turbine rotor is disclosed, which comprises the steps of injection molding a rotor body including a conical shaft and a plurality of blades formed on the periphery of the shaft and at an angle to the axis of the shaft from a ceramic material using a mold having parting lines corresponding to blade edges such that projections are formed on the blade edges, sintering the molding thus obtained, and grinding the edge surfaces of the blades facing a casing. The blades are thus provided with projections on their inlet and outlet edges which face a fluid passage.

Abstract: A valve for an internal combustion engine formed of ceramic material for resistance to corrosion, heat and wear. The valve may include a valve tip, a lock groove, a valve stem, a valve fillet, a valve face, a valve margin and a valve head. Certain portions of the valve, such as the valve tip, the lock groove and the valve stem may, alternatively, be formed of metal. The ceramic material includes, among other compositions, silicon nitride, silicon carbide, aluminum nitride, silicon oxynitride, silicon aluminum oxynitride and silicon nitride-silicon carbide.

Abstract: An apparatus for making a single crystal which includes a sealed vessel, a crucible received in the sealed vessel to hold a molten liquid and a floating member having an opening for defining the cross sectional outline of a single crystal while being grown and floating on the molten liquid. The floating member is made from a sintered body consisting essentially of at least one of the oxides of yttrium and the lanthanum series elements, aluminum oxide, aluminum nitride and silicon nitride each in a prescribed amount.

Abstract: An article has a portion contacted by gallium phosphide or gallium arsenide. At least the contacting portion is formed of a sintered body of a mixture of silicon nitride and an additive, and part or the whole of the additive is present as a crystallized phase in the sintered silicon nitride system.

Abstract: Composite ceramic articles formed by integrally assembling a plurality of previously molded constituent members without applying an adhesive to their joints and designed to have a density higher than 98% of the theoretical value, and a flexural strength greater than 50 kg/cm.sup.2 at 1200.degree. C., and a method of producing ceramic articles of particularly complex shape which comprises the steps of previously molding a plurality of constituent members of complex shape and later integrally assembling said constituent members without applying an adhesive to their joints.

Abstract: Composite ceramic articles formed by integrally assembling a plurality of previously molded constituent members without applying an adhesive to their joints and designed to have a density than higher 98% of the theoretical value, and a flexural strength greater than 50 kg/cm.sup.2 at 1200.degree. C., and a method of producing ceramic articles of particularly complicated shape which comprises the steps of previously molding a plurality of constituent members of complicated shape and later integrally assembling said constituent members without applying an adhesive to their joints.