Abstract: A silicon carbide powder for the production of a silicon carbide single crystal has an average particle diameter of 100 ?m or more and 700 ?m or less and a specific surface area of 0.05 m2/g or more and 0.30 m2/g or less. A method for producing a silicon carbide powder for the production of the silicon carbide single crystal including sintering a silicon carbide powder having an average particle diameter of 20 ?m or less under pressure of 70 MPa or less at a temperature of 1900° C. or more and 2400° C. or less and in a non-oxidizing atmosphere, thereby obtaining a sintered body having a density of 1.29 g/cm3 or more; adjusting particle size by means of pulverization of the sintered body; and removing impurities by means of an acid treatment.

Abstract: Provided is a manufacturing device of an aluminum nitride single crystal including a crucible. An aluminum nitride raw material and a seed crystal are stored in an inner portion of the crucible. The seed crystal is placed so as to face the aluminum nitride raw material. The crucible includes an inner crucible and an outer crucible. The inner crucible stores the aluminum nitride raw material and the seed crystal inside the inner crucible. The inner crucible is also corrosion resistant to a sublimation gas of the aluminum nitride raw material. The inner crucible includes either, a single body of a metal having an ion radius larger than an ion radius of an aluminum, or includes a nitride of the metal. The outer crucible includes a boron nitride. The outer crucible covers the inner crucible.

Abstract: A silicon carbide powder for the production of a silicon carbide single crystal has an average particle diameter of 100 ?m or more and 700 ?m or less and a specific surface area of 0.05 m2/g or more and 0.30 m2/g or less. A method for producing a silicon carbide powder for the production of the silicon carbide single crystal including sintering a silicon carbide powder having an average particle diameter of 20 ?m or less under pressure of 70 MPa or less at a temperature of 1900° C. or more and 2400° C. or less and in a non-oxidizing atmosphere, thereby obtaining a sintered body having a density of 1.29 g/cm3 or more; adjusting particle size by means of pulverization of the sintered body; and removing impurities by means of an acid treatment.

Abstract: The invention is an apparatus for production of an aluminum nitride single crystal that produces the aluminum nitride single crystal by heating an aluminum nitride raw material to sublimate the raw material, thereby to recrystallize the aluminum nitride onto a seed crystal, which includes a growth vessel that accommodates the aluminum nitride raw material, and is composed of a material that has corrosion resistance with respect to the aluminum gas generated upon sublimation of the aluminum nitride raw material, and a heating element that is arranged on the outside of the growth vessel, and heats the aluminum nitride raw material through the growth vessel, wherein the growth vessel includes a main body which has an accommodation section that accommodates the aluminum nitride and a lid which seals the accommodation section of the main body hermetically, and wherein the heating element is composed of a metal material containing tungsten.

Abstract: Provided is a manufacturing device of an aluminum nitride single crystal including a crucible. An aluminum nitride raw material and a seed crystal are stored in an inner portion of the crucible. The seed crystal is placed so as to face the aluminum nitride raw material. The crucible includes an inner crucible and an outer crucible. The inner crucible stores the aluminum nitride raw material and the seed crystal inside the inner crucible. The inner crucible is also corrosion resistant to a sublimation gas of the aluminum nitride raw material. The inner crucible includes either, a single body of a metal having an ion radius larger than an ion radius of an aluminum, or includes a nitride of the metal. The outer crucible includes a boron nitride. The outer crucible covers the inner crucible.

Abstract: A machine tool includes X-axis, Y-axis, and Z-axis moving units for producing relative movements between a tool and a workpiece; a C-axis drive unit for rotating the workpiece about a C-axis parallel to the Z-axis; and a B-axis turning unit for turning the tool about a B-axis parallel to the Y-axis. The tool is disposed in such a manner that a machining point of the tool coincides with the B-axis. The moving units, the drive unit, and the turning unit are controlled in such a manner that a work point of the workpiece coincides with the machining point of the tool. The bed is formed through casting and has a hollow structure and a hole as cast; and a cover is provided to cover the hole as cast in order to close the interior of the bed.

Abstract: A machine tool includes X-axis, Y-axis, and Z-axis moving units for producing relative movements between a tool and a workpiece; a C-axis drive unit for rotating the workpiece about a C-axis parallel to the Z-axis; and a B-axis turning unit for turning the tool about a B-axis parallel to the Y-axis. The tool is disposed in such a manner that a machining point of the tool coincides with the B-axis. The moving units, the drive unit, and the turning unit are controlled in such a manner that a work point of the workpiece coincides with the machining point of the tool. The bed is formed through casting and has a hollow structure and a hole as cast; and a cover is provided to cover the hole as cast in order to close the interior of the bed.

Abstract: A machine tool includes X-axis, Y-axis, and Z-axis moving units for producing relative movements between a tool and a workpiece; a C-axis drive unit for rotating the workpiece about a C-axis parallel to the Z-axis; and a B-axis turning unit for turning the tool about a B-axis parallel to the Y-axis. The tool is disposed in such a manner that a machining point of the tool coincides with the B-axis. The moving units, the drive unit, and the turning unit are controlled in such a manner that a work point of the workpiece coincides with the machining point of the tool. The bed is formed through casting and has a hollow structure and a hole as cast; and a cover is provided to cover the hole as cast in order to close the interior of the bed.