In an embodiment a conversion element includes a first phase and a second phase, wherein the first phase comprises lutetium, aluminum, oxygen and a rare-earth element, wherein the second phase comprises Al.sub.2O.sub.3 single crystals, and wherein the conversion element comprises at least one groove.

The present invention provides a high alumina fused cast refractory that is easily produced and has low porosity and high corrosion resistance, and a method of producing the same. The high alumina fused cast refractory of the present invention has the following chemical composition: 95.0 mass % to 99.5 mass % Al.sub.2O.sub.3, 0.20 mass % to 1.50 mass % SiO.sub.2, 0.05 mass % to 1.50 mass % B.sub.2O.sub.3, 0.05 mass % to 1.20 mass % MgO and balance. The method of producing the high alumina fused cast refractory of the present invention includes obtaining a mixture by mixing an Al.sub.2O.sub.3 source material, a SiO.sub.2 source material, a B.sub.2O.sub.3 source material and an MgO source material, and fusing the mixture.

Provided is a polycrystalline ceramic substrate to be bonded to a compound semiconductor substrate with a bonding layer interposed therebetween, wherein at least one of relational expression (1) 0.7<α.sub.1/α.sub.2<0.9 and relational expression (2) 0.7<α.sub.3/α.sub.4<0.9 holds, where α.sub.1 represents a linear expansion coefficient of the polycrystalline ceramic substrate at 30° C. to 300° C. and α.sub.2 represents a linear expansion coefficient of the compound semiconductor substrate at 30° C. to 300° C., and α.sub.3 represents a linear expansion coefficient of the polycrystalline ceramic substrate at 30° C. to 1000° C. and α.sub.4 represents a linear expansion coefficient of the compound semiconductor substrate at 30° C. to 1000° C.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

There is provided at least any of a layered body which has a change in color tone and in which it is unnecessary to select a colorant and the content of the colorant in consideration of a difference in the sintering behavior between layers, a precursor thereof, or a method for producing these. Provided is a layered body which has a structure, in which two or more layers containing stabilizer-containing zirconia and a colorant are layered, and in which types and contents of the colorants contained in the layers are equal to each other, the layered body including at least: a first layer containing a colorant and zirconia which has a stabilizer content of higher than or equal to 3.3 mol %; and a second layer containing a colorant and zirconia which has a stabilizer content different from that of the zirconia contained in the first layer.

An extrudable ceramic precursor mixture and method of use includes: an inorganic ceramic-forming component, a first siloxane prepolymer, a second siloxane prepolymer with a different composition than the first siloxane prepolymer, a catalyst adapted to catalyze polymerization of the first siloxane prepolymer with the second siloxane prepolymer into a siloxane-based polymer, and a thermally curable siloxane-based cross-linking agent adapted to crosslink the siloxane-based polymer. Comprised is a polydimethylsiloxane having a vinyl functional group and a polydimethylsiloxane having a silicon hydride functional group.

A full-fiber burner brick and a preparation method thereof, comprising mixing alumina crystal fiber and amorphous ceramic fiber with both of them being a combination of fibers of different lengths gradations, and moreover adding fine powder fillers of different particle size gradations and supplementing other additives. This enables the internal structure of the product more uniform, increases the bulk density of the product, and also benefits the suction filterability of fiber cotton blank, and is conducive to forming and improving the strength of the blank. The surface of the brick body is further provided with a coating, which can effectively protect the cotton fiber of the brick body fiber from harsh environments, improve its high temperature resistance, and help to extend the service life of the burner brick.

A heat dissipation member includes a thermal radiation ceramic material, and the thermal radiation ceramic material contains silicon nitride and boron nitride as main components. The ratio of the mass of boron nitride to the mass of silicon nitride and boron nitride is 10 mass % to 40 mass %.

The present invention relates to a ceramic solid electrolyte, which is a key component of an all-solid-state lithium secondary battery, for improving safety, and a method for synthesizing the same. The present invention relates to an oxide-based conductive ceramic of a new NASICON structure of the chemical formula Li.sub.1+xAl.sub.xX.sub.2−xP.sub.3O.sub.12 (X is Zr, Si, Sn, or Y, 0<x<2) or Li.sub.1+xZr.sub.2X.sub.xP.sub.3−xO.sub.12 (X=Si, Sn, Ge, or Y, 1.5≤x≤2.3). The present invention relates to a method for manufacturing an oxide-based conductive ceramic having the above novel NASICON structure.

The present invention relates to a method for producing a metal nitride by igniting a raw material powder containing a metal powder filled in a reaction vessel under a nitrogen atmosphere and propagating nitriding combustion heat generated by a nitriding reaction of the metal to the whole raw material powder, the method including forming a heat insulating layer made of a material having nitrogen permeability and inert to the nitriding reaction on an upper surface of a layer made of the raw material powder. According to the present invention, it is possible to provide a method for reducing the amount of unreacted metal powder when producing a metal nitride by a combustion synthesis method.