Abstract: Silicon carbide single crystal is produced by allowing a silicon raw material to continuously react with a carbon raw material to generate gas, which reaches a seed crystal substrate on which a silicon carbide single crystal grows. Preferably, the silicon raw material is continuously fed onto the carbon raw material placed in a reaction crucible, and the carbon raw material is maintained at a temperature such that carbon is allowed to react with silicon in a molten state or a gaseous state to generate the reaction gas.

Abstract: Silicon carbide single crystal is produced by allowing a silicon raw material to continuously react with a carbon raw material to generate gas, which reaches a seed crystal substrate on which a silicon carbide single crystal grows. Preferably, the silicon raw material is continuously fed onto the carbon raw material placed in a reaction crucible, and the carbon raw material is maintained at a temperature such that carbon is allowed to react with silicon in a molten state or a gaseous state to generate the reaction gas.

Abstract: A thin strip-shaped grindstone 12 is held flat under tension and moved backwards and forwards in the longitudinal direction, while the grindstone is moved in a direction perpendicular to a cylindrical ingot 1 and cuts the ingot. A metal-bonded grindstone is used as the strip-shaped grindstone 12, at least one pair of electrodes 23 are disposed adjacent to both surfaces of the metal-bonded grindstone one on each side of the ingot. The metal-bonded grindstone is made the positive electrode and DC voltage pulses are applied between the grindstone and the electrodes, and at the same time, a conducting processing fluid 25 is fed to the gaps between the metal-bonded grindstone and the electrodes, and both surfaces of the metal-bonded grindstone are dressed electrolytically on both sides while the cylindrical ingot is being cut by the metal-bonded grindstone.

Abstract: Silicon carbide single crystal is produced by allowing a silicon raw material to continuously react with a carbon raw material to generate gas, which reaches a seed crystal substrate on which a silicon carbide single crystal grows. Preferably, the silicon raw material is continuously fed onto the carbon raw material placed in a reaction crucible, and the carbon raw material is maintained at a temperature such that carbon is allowed to react with silicon in a molten state or a gaseous state to generate the reaction gas.

Abstract: A process for producing a silicon carbide single crystal and a production apparatus therefor which enable, under stable conditions, continuous production of a silicon carbide single crystal which has a reduced density and dispersion of crystal defects in a growth direction, no lattice distortion, a large diameter, and constant quality. A melted or vaporized silicon material is introduced from the outside of a reaction system into a carbon material heated to a temperature equal to or higher than a temperature at which the silicon material vaporizes; and a reaction gas containing silicon gas and silicon carbide gas generated by a reaction between the carbon material and the silicon material is caused to reach a silicon carbide seed crystal substrate 5 which is held at a temperature lower than that of the carbon material, so that a silicon carbide single crystal grows on the silicon carbide seed crystal substrate.

Abstract: Silicon carbide single crystal is produced by allowing a silicon raw material to continuously react with a carbon raw material to generate gas, which reaches a seed crystal substrate on which a silicon carbide single crystal grows. Preferably, the silicon raw material is continuously fed onto the carbon raw material placed in a reaction crucible, and the carbon raw material is maintained at a temperature such that carbon is allowed to react with silicon in a molten state or a gaseous state to generate the reaction gas.

Abstract: A tube is formed from a polycrystalline silicon carbide having a density of from 3.18 to 3.21 g/cm.sup.3, a maximum impurity content of 20 ppm, and imperviousness to fluids by a process which comprises precipitating the silicon carbide on the surface of a rod-shaped graphite structure by a chemical vapor-phase synthesis method and thereafter removing the graphite structure. A water-jet nozzle of high resistance to abrasive wear can be produced by using this tube as an inner tube thereof to form the flow path for a water jet to be ejected therethrough.