An oxide superconductor includes: REBa.sub.2Cu.sub.3O.sub.7-x (RE being one element selected from a “RE element group” of Pr, Nd, Sm, Eu, Gd, Y, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The RE includes at least three, types of metallic elements (M1, M2, and M3), and the three types of metallic elements are any element of the RE element group selected in order. In an oxide system satisfying R(1)≦20 mol % and R(M2)≧60 mol % and R(M3)≦20 mol %, R(M1) being an average metallic element ratio of M1 in M1+M2+M3, SD(Ms)>0.15 is satisfied at a position at 50% of an average film thickness of a cross section including the c-axis, Ms being the metallic element of not larger of R(M1) and R(M3), SD(Ms) being a standard deviation/average value of a concentration of Ms.

Provided is a powder material for producing a three-dimensional object including: a base material; a resin; and resin particles, wherein an amount W (mass %) of carbon remaining in the powder material after heating in a vacuum of 10.sup.−2 Pa or lower at 450 degrees C. for 2 hours satisfies the following formula: W (mass %)<0.9/M, where M represents the specific gravity of the base material.

A carbon ceramic brake disc according to the present invention includes: a support body having cooling channels at the center portion; and friction layers directly attached to the top and the bottom of the support body without a bonding layer and having components different from the components of the support body, in which the support body is composed of a plurality of layers having components similar to the friction layers, gradually toward the friction layers from the cooling channels as the center. Accordingly, the support body can perform thermomechanical shock absorbing that is an original function and the friction layers and the support body can be prevented from separating while the carbon ceramic brake disc is manufactured.

Low-carbon monolithic refractories are provided. Methods of manufacturing glass employing low-carbon monolithic refractories are also provided. Methods and apparatuses for glass manufacture for reducing the formation of carbon dioxide blisters during glass manufacture are also provided.

A method of preparing a fine powder of calcium lanthanoid sulfide is disclosed. The method includes spraying soluble calcium and lanthanoid salts into at least one precipitating solution to form a precipitate comprising insoluble calcium and lanthanoid salts, optionally, oxidizing the precipitate comprising insoluble calcium and lanthanoid salts, and sulfurizing the optionally oxidized precipitate to form a fine powder of calcium lanthanoid sulfide. An alternative method for forming the powder is by flame pyrolysis. The calcium lanthanoid sulfide powder produced by either method can have an impurity concentration of less than 100 ppm, a carbon concentration of less than 200 ppm, a BET surface area of at least 50 m.sup.2/g, and an average particle size of less than 100 nm.

Refractory transition metal-carbide (RTM-C) fibers were synthesized via the Forcespinning™ method. This method allows for simple and rapid synthesis of these RTM-C fibers with the ability to make grams of fibers quickly.

A method for producing a silicon carbide sintered body, comprising adding water to a raw material mixture containing silicon carbide powder, at least one binder, and optionally at least one carbon source other than the silicon carbide and the at least one binder, and subjecting the raw material mixture to kneading, molding, and drying in this order, to obtain a dried body; heating the dried body to remove organic substances from the dried body to obtain a degreased body; and firing the degreased body in an inert atmosphere to obtain a silicon carbide sintered body. The method comprises controlling an expansion/shrinkage rate of the sintered body by adjusting at least one of (1) an amount of the at least one carbon source in the raw material mixture, (2) an amount of the at least one binder in the raw material mixture, and (3) a degreasing rate.

The invention concerns a batch for the production of a refractory product, a process for the production of a refractory product, a refractory product as well as the use of a refractory product.

Hafnium carbide powder for plasma electrodes is represented by a chemical formula HfC.sub.x (where x=0.5 to 1.0). The content of carbon particles contained as impurities in the hafnium carbide powder is less than or equal to 0.03% by mass. The hafnium carbide powder preferably has an average particle size of 0.5 to 2 μm. To produce the hafnium carbide powder, a pellet made from mixed powder of hafnium oxide and carbon is first placed in a second crucible made of silicon carbide. Then, the hafnium carbide powder is formed by heating the second crucible at 1800 to 2000° C. with the second crucible arranged in a first crucible made of carbon.

Color unevenness generated on a surface of a silicon nitride substrate is reduced. A silicon nitride substrate formed by nitriding silicon containing in a sheet-shaped green body includes a first surface and a second surface opposite to the first surface. In this case, when color difference between a center and an edge of at least one surface of the first surface and the second surface is expressed to be “ΔE*ab”, a relation “ΔE*ab≤1.5” is established.