Sumitomo Electric Industries, Limited

Harutoshi Ukegawa

Masuhiro Natsuhara

Matsuo Higuchi

Hirohiko Nakata

Kazutaka Sasaki

Kouhei Shimoda

Kazuya Kamitake

Akira Yamakawa

Takao Nishioka

Nobuyuki Kitagawa

Shingo Hirota

Aluminium nitride ceramics and method for preparing the same

The ceramic insert made from a silicon nitride ceramic material and formed with a recess for fastening in the center of its rake face. The recess has a surface roughness Rmax not exceeding 4 .mu.m. The angle between a side face of the recess and a centerline perpendicular to the rake face of the insert is 50-70 degrees. The ratio of the diameter of the recess to the diameter of a circle inscribing the perimeter of the rake face is 30-85%. The recess has a flat or curved bottom. The connecting portion between the side face and the bottom of the recess forms a smoothly curved surface.

Ceramic insert for use with clamp type cutting tool

Aluminium nitride ceramics improved in heat radiation property used as a substrate for integrated circuits and package material, comprising a sintered article consisting mainly of aluminium nitride and having a thermal conductivity higher than 100.multidot.W/m.multidot.K at room temperature and a surface layer consisting mainly of aluminium nitride or oxide glass deposited on the sintered article. A paste of aluminium nitride powder or oxide glass powder is coated on a surface of the sintered article of aluminium nitride and then is sintered to prepare a dense smooth surface layer.

A sintered silicon nitride-based body comprising 20% or less by weight of a grain boundary phase and the balance being a major phase of grains of silicon nitride and/or sialon, wherein the major phase contains a grain phase of a .beta.-Si.sub.3 N.sub.4 phase and/or a .beta.'-sialon phase, and a quantitative ratio of the grain phase of the .beta.-Si.sub.3 N.sub.4 phase and/or the .beta.'-sialon phase is in a range of 0.5 to 1.0 relative to the major phase; the grain boundary phase contains Re.sub.2 Si.sub.2 O.sub.7 (wherein Re represents a rare-earth element other than Er and Yb) as a first crystal component and at least one of ReSiNO.sub.2, Re.sub.3 Al.sub.5 O.sub.12, ReAlO.sub.3, and Si.sub.3 N.sub.4.Y.sub.2 O.sub.3 as a second crystal component; and a quantitative ratio of the first and second crystal components in the grain boundary phase to the grain phase of .beta.-Si.sub.3 N.sub.4 phase and/or the .beta.'-sialon phase ranges from 0.03 to 1.6. The sintered body is produced by mixing a specific sintering aid and silicon nitride-based powder, sintering the mixture and heat treating the sintered body for nucleation and crystal growth within the temperature range of from 1050.degree. to 1550.degree. C.

Sintered silicon nitride-based body and process for producing the same

Aluminum nitride ceramics and method for preparing the same

Sintered silicon nitride-based body

A structure for mounting a semiconductor device includes a ceramic plate having a thermal conductivity equal to or higher than 120 W/mK on one surface of which the semiconductor device is mounted, a heat sink joined to another surface of the ceramic plate formed of a copper or copper based alloy plate having a thermal conductivity equal to or higher than 300 W/mK, and a base member formed of a metal or an alloy having a thermal conductivity equal to or higher than 100 W/mK on which the heat sink is mounted.

Mounting structure for semiconductor device having low thermal resistance

A zirconia vane used in a rotary compressor, the zirconia vane being formed of a partially stabilized zirconia sintered body containing 92 through 98 molar percent of ZrO.sub.2 and being stabilized with Y.sub.2 O.sub.3, zirconia crystals constituting the zirconia sintered body having a mean grain diameter of 0.1 to 0.6 .mu.m and a maximum grain diameter of not greater than 2 .mu.m, the zirconia sintered body having a mean three-point flexural strength of not less than 120 kg/mm.sup.2 measured in conformity with JIS R1601, a surface of the zirconia sintered body in contact with a rotor of the rotary compressor having a first surface roughness in a direction of rotations of the rotor, specified by a ten-point mean roughness Rz, of not greater than 1 .mu.m and a second surface roughness in a direction perpendicular to the direction of rotation of the rotor, specified by the ten-point mean roughness Rz, of not greater than 0.6 .mu.m. The vane is light-weight and has excellent sliding properties to effectively prevent cohesion and seizure in an atmosphere of a coolant of chlorine-free like an HFC.

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Hyogo, Japan

Harutoshi Ukegawa