A castable refractory composition may include from 5% to 95% by weight of alumina, aluminosilicate, or mixtures thereof; from 0.5% to 1.5% by weight alkaline earth metal oxide and/or hydroxide, and 0.1% to 5% by weight of silica having a surface area of at least about 10 m.sup.2/g. The refractory composition may include no more than 0.5% by weight of cementitious binder. The refractory composition may release less than 25 cm.sup.3 of hydrogen gas per kilogram of castable refractory composition upon addition of water. The refractory compositions may set on addition of water.

A method of producing ceramic wafer includes a forming step and processing step. The processing step includes forming positioning notch or positioning, flat edge and edge profile, which avoids the ceramic wafers to have processing defect during cutting, grinding, and polishing, for increasing yield. The ceramic particles for producing ceramic wafer include nitride ceramic powder, oxide ceramic powder, and nitride ceramic powder. The ceramic wafer has low dielectric constant, insulation, and excellent heat dissipation, which can be applied for the need of semiconductor process, producing electric product and semiconductor equipment.

The present invention relates to the use of closed-pore microspheres of expanded perlite as a filler for producing moldings for the foundry industry, to a composition for producing moldings for the foundry industry, comprising closed-pore microspheres of expanded perlite as a filler, and a binder, the binder being selected from the group consisting of water glass, phenol-formaldehyde resins, two-component systems comprising as reactants a polyisocyanate and a polyol component containing free hydroxyl groups (OH groups), and starch, and also to moldings for the foundry industry and to a process for producing a molding for the foundry industry.

The present invention relates to a novel process for producing ceramic materials, in particular refractory materials having a reduced relative density. In particular, the invention relates to a process for producing light, refractory materials having non-contiguous pores based on shaped and unshaped materials. These materials can be used as working lining in high-temperature applications. The process is based on the production of spherical, closed and isolated pores in the microstructure of the material. The pores having a pore diameter which can be set in a targeted manner are generated by use of polymer particles, in particular polymethacrylates, in particular polymers or copolymers prepared by means of suspension polymerization, as pore formers which can be burnt out. The polymers or copolymers are present in the form of small spheres having a defined diameter. The introduction of isolated spherical pores allows the production of ceramic materials having a sometimes significantly reduced relative density and improved corrosion resistance and better mechanical strength compared to the prior art. The specific, closed pore system at the same time contributes to reducing the thermal conductivity of the ceramic materials. In addition, the novel process has the advantage that there is no risk of formation of undesirable black cores, even in the production of thick-walled ceramic products.

A method for manufacturing a part made of ceramic matrix composite (CMC) material includes producing a fibrous preform from silicon carbide fibres; consolidating the fibrous preform by gas-phase chemical infiltration; injecting a slurry including a silicon carbide particle powder into the consolidated fibrous preform; and densifying by infiltrating the preform with a composition based on molten silicon to give a part made of CMC material. The slurry further includes at least one organic binder. The method includes, prior to the infiltrating of the preform with a composition based on molten silicon, pyrolysing the organic binder so as to form a carbon-containing residue in the fibrous preform.

A castable refractory composition may include from 5% to 95% by weight of alumina, aluminosilicate, or mixtures thereof; from 0.5% to 1.5% by weight alkaline earth metal oxide and/or hydroxide, and 0.1% to 5% by weight of silica having a surface area of at least about 10 m.sup.2/g. The refractory composition may include no more than 0.5% by weight of cementitious binder. The refractory composition may release less than 25 cm.sup.3 of hydrogen gas per kilogram of castable refractory composition upon addition of water. The refractory compositions may set on addition of water.

Provided is a green sheet, comprising a raw material powder and a binder resin, in which the raw material powder contains a silicon nitride powder, and a glass transition temperature of the binder resin is less than 20 C.

A dry prepreg of fibrous textile/thermoplastic with handling characteristics highly compatible with robotic handling and a method for making at least one dry prepreg and forming the at least one dry prepreg over a mold form. The method also includes using the at least one molded dry prepreg as at least one sub-laminate in a thermoforming process. The methods include CMC preforming processes which can be automated though the use of robotic handling devices.