A refractory material contains: 40 mass % or more of MgO; 4 to 30 mass % of a free carbon component; and one or more of B.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2 and TiO.sub.2, in a total amount of 0.3 to 3 mass %, with the remainder being at least one other type of additional refractory component. A void layer exists in an interface between a carbon-containing matrix microstructure residing at least on opposite sides of a maximum-size one of a plurality of MgO-containing particles in the refractory material, and the maximum-size MgO-containing particle. A sum of respective thicknesses of the void layer at two positions on the opposite sides is 0.2 to 3.0% of a ratio with respect to particle size of the maximum-size MgO-containing particle. An inorganic compound of MgO and the one or more of B.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2 and TiO.sub.2 exists entirety or partially in a surface of each of the MgO-containing particles.

A process for preparing alloy products is described using a self-sustaining or self-propagating SHS-type combustion process with point-source ignition, preferably a laser, in a pressurized vessel. Binary, ternary and quaternary alloys can be formed with control over polycrystalline structure and bandgap. Methods to tune the bandgap and the alloys formed are described. The alloy products may be doped. Preferably sulfides, tellurides or selenides are formed. Cooling during reaction takes place.

The object of the present invention is to provide a large-sized gallium nitride-based sintered body having a small oxygen amount and high strength, a large-sized gallium nitride-based sintered body having a small oxygen amount and containing a dopant, to obtain a highly crystalline gallium nitride thin film which has become a n-type or p-type semiconductor by a dopant, and methods for producing them.

A gallium nitride-based sintered body, which has an oxygen content of at most 1 atm % and an average particle size (D50) of at least 1 μm and at most 150 μm.

Disclosed is a refractory product for casting of steel, which is capable of forming a dense surface layer which is high in terms of a slag infiltration suppressing ability and strong, in a surface region thereof efficiently or sufficiently or in an optimum state. The refractory product contains 1 mass % or more of free carbon, and 2 mass % to 15 mass % of an aluminum component as metal, with the remainder comprising a refractory material as a main composition, wherein the refractory product has a permeability of 1×10.sup.−16 m.sup.2 to 15×10.sup.−16m.sup.2.

A dielectric material includes a main component represented by (Ba.sub.1-xCa.sub.x)(Ti.sub.1-y(Zr, Sn, Hf).sub.y)O.sub.3 (0≤x≤1 and 0≤y≤0.5); a first subcomponent including at least one of elements among Y, Dy, Ho, Er, Gd, Ce, Nd, Nb, Sm, Tb, Eu, Tm, La, Lu, and Yb; a second subcomponent including Si and/or Al; and a third subcomponent including Ba and/or Ca.

A dielectric ceramic composition and a multilayer ceramic capacitor including the same are provided. The dielectric ceramic composition includes a BaTiO.sub.3-based base material main ingredient and an accessory ingredient, where the accessory ingredient includes dysprosium (Dy) and niobium (Nb) as first accessory ingredients. A total content of the Dy and Nb is less than or equal to 1.5 mol, based on 100 mol of Ti of the base material main ingredient, and a content of the Dy satisfies 0.7 mol<Dy<1.1 mol, based on 100 mol of Ti of the base material main ingredient.

A method of making an Al—B.sub.4C composite with Mg addition comprising providing a first mixture of B.sub.4C, Al and Mg powder, producing a powder mixture, adding Mg to the powder mixture, forming pellets, creating a composite, annealing the composite, and forming an Al—Mg—B.sub.4C composite. An Al—B.sub.4C composite with Mg addition comprising Al, Mg comprising 4 wt. %, and B.sub.4C comprising 8 wt. %. An Al—B.sub.4C composite with Mg addition made from the steps comprising providing a first mixture of B.sub.4C, Al and Mg powder, producing a powder mixture, adding Mg to the powder mixture, forming pellets, creating a composite, annealing the composite, and forming an Al—Mg—B.sub.4C composite.

A Cr:YAG sintered body including Al, Y, Cr, Ca, Mg, Si, and O, and component contents in the sintered body satisfying conditional expressions of 1) to 3) below, provided in the Conditional expression, each chemical symbol represents a component content (atppm).
|(Y+Ca)/(Al+Cr+Si+Mg)−0.6|<0.001;  1)
0≤(Ca+Mg)−(Cr+Si)≤50 atppm; and  2)
50≤Si≤500 atppm  3) The embodiment of the present invention is to provide a Cr:YAG sintered body which exhibits high transparency and has a high Cr.sup.4+ conversion ratio, and its production method.

A thermoelectric conversion material made of a sintered body containing a magnesium silicide as a major component includes: a magnesium silicide phase; and a magnesium oxide layer formed on a surface layer of the magnesium silicide phase, in which an aluminum concentrated layer having an Al concentration higher than an aluminum concentration in an inside of the magnesium silicide phase is formed between the magnesium oxide layer and the magnesium silicide phase, and the aluminum concentrated layer has a metallic aluminum phase including aluminum or an aluminum alloy.

A dielectric ceramic composition and a multilayer ceramic capacitor including the same are provided. The dielectric ceramic composition includes a BaTiO.sub.3-based base material main ingredient and an accessory ingredient, where the accessory ingredient includes dysprosium (Dy) and niobium (Nb) as first accessory ingredients. A total content of the Dy and Nb is less than or equal to 1.5 mol, based on 100 mol of Ti of the base material main ingredient, and a content of the Dy satisfies 0.7 mol<Dy<1.1 mol, based on 100 mol of Ti of the base material main ingredient.