A method for preparing a boron carbide material includes: providing raw materials of a boron material, a carbon material and a rare earth oxide, wherein an element molar ratio B:C of the boron material to the carbon material is in a range of 4:1 to 4:7, and the rare earth oxide is in an amount of 5 wt % or less based on a total weight of the raw materials, mixing and milling the raw materials to obtain a mixture, compressing the mixture into a tablet form by a tablet press, and sintering the compressed mixture by a laser, wherein the laser has a laser wavelength of 980 nm, a laser power in a range of 100 to 3000 W, and a laser irradiation time of 3 to 60 s.

A spray material for hot and dry spray application with improved corrosion resistance, and a hot and dry spray application method with improved corrosion resistance. A hot and dry spray application method comprises pressure-feeding a mixture comprising a refractory material and a binder, toward a spraying nozzle via a pipe, and adding water to the mixture at a distal end of the spraying nozzle to apply a spray under a hot condition. The mixture contains magnesium limestone having a particle size of 0.075 mm to less than 1 mm, in an amount of 10 mass % to 50 mass %, in 100 mass % of a total amount of the refractory material and the binder. The content of magnesium limestone having a particle size of less than 0.075 mm in 100 mass % of the total amount of the refractory material and the binder is 35 mass % or less (including 0).

To provide a dense beta-alumina-based sintered compact having a high ionic conductivity as a solid electrolyte by firing at a low temperature to suppress the volatilization of Na.sub.2O and its production method. By adding RNbO.sub.3 which is a material having a low melting point to a beta-alumina powder, followed by firing, it is possible to obtain a beta-alumina-based sintered compact having a low firing temperature and containing, as the main component, dense β″ alumina crystals which are free from anomalous grain growth during the firing process.

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 self-lubricating flexible carbon composite seal includes an annular body formed from a flexible carbon composite.

A process for producing a refractory material for use in the superstructure of glass melting tanks contains, as main components, SiO.sub.2, SiC and a binder or binder mixture. A particulate substance, which in the spectral range from 1 μm to 5 μm and at temperatures above 1000° C. has a spectral emission capability which is higher than the spectral emission capability of the matrix of the refractory material, is incorporated into the matrix of the refractory material. A method of increasing the spectral emissivity of shaped, fired, refractory materials, is also provided.

A method of making a plurality of composite granules can include: forming green body granules comprising an aluminosilicate; heating the green body granules to form sintered granules; cooling the sintered granules according to a cooling regime, wherein the cooling regime comprises a temperature hold between 700° C. and 900° C. for at least one hour. In a particular embodiment, the aluminosilicate for making the composite granules can have a particle size less than 150 μm. The composite granules are particularly suitable as roofing granules and can have a desired combination of high solar reflectance SR and low lightness L*, a low bulk density, good weather resistance and strength.

A solid composition contains a first material and a powder and satisfies requirements 1 and 2. Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at least at −200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the powder)/(a c-axis lattice constant of a crystal in the powder), obtained from X-ray diffractometry of the powder. Requirement 2: C is 0.04 or more. C is (a log differential pore volume when a pore diameter of the solid composition is B in a pore distribution curve of the solid composition)/(a log differential pore volume corresponding to a maximum peak intensity in the pore distribution curve of the solid composition). B is (a pore diameter giving a maximum peak intensity in the pore distribution curve of the solid composition)/2. The pore distribution curve of the solid composition shows a relationship between the pore diameter and the log differential pore volume.

Particles for a monolithic refractory are made of a spinet porous sintered body which is represented by a chemical formula of MgAl.sub.2O.sub.4, wherein pores having a pore size of 0.01 μm or more and less than 0.8 μm occupy 10 vol % or more and 50 vol % or less with respect to a total volume of pores having a pore size of 10 μm or less in the particles, and the particles for a monolithic refractory have grain size distribution in which particles having a particle size of less than 45 μm occupy 60 vol % or less, particles having a particle size of 45 μm or more and less than 100 μm occupy 20 vol % or more and 60 vol % or less, and particles having a particle size of 100 μm or more and 1000 μm or less occupy 10 vol % or more and 50 vol % or less.

Disclosed is a technique for suppressing a firing property and a dust generating property while improving bondability, in a thermal spray material for use in a thermite spraying process. The thermal spray material comprises a refractory material powder and a metal Si powder and capable of being sprayed onto a target surface using oxygen or oxygen-containing gas as a carrier gas and melt-adhered to the target surface based on heat generated by combustion of the metal Si powder, wherein the metal Si powder is contained in an amount of 10 to 25 mass % with respect to the entire thermal spray material, and wherein the metal Si powder has a median size of 10 μm or less, and contains a fraction having a particle size of 2 μm or less in an amount of 8 mass % or less with respect to the entire metal Si powder.