Kabushiki Kaisha Toshiba

Tokyo Shibaura Electric Co., Ltd.

Tokyo Shibaura Denki Kabushiki Kaisha

Toshiba Materials Co., Ltd.

Michiyasu Komatsu

Akihiko Tsuge

Tadashi Miyano

Katsutoshi Nishida

Kazuo Ikeda

Yoshitoshi Sato

Takashi Ishii

Katsutoshi Komeya

Hiroshi Komorita

Nobuyuki Mizunoya

Minoru Takao

Masae Nakanishi

Kimiya Miyashita

Takayuki Naba

Kiyoshi Nakamura

Isao Ikeda

Akio Ando

Yoshiyuki Fukuda

Tsuneji Kameda

Masahiro Asayama

Akio Sayano

Hisao Yabe

Takao Shirai

Katsuhiro Shinosawa

Hiroyasu Ohta

Hiroki Tonai

Yukihiro Takenami

Hideki Yamaguchi

Hiroshi Inoue

Yasuhiro Goto

Hiromasa Kato

Katsuyuki Aoki

Shun-ichiro Tanaka

Shoko Suyama

Yutaka Abe

Noritaka Nakayama

Kai Funaki

Takeyuki Yonezawa

Syoji Okada

Haruhiko Yamaguchi

Haruhiko Yamaguti

Kazuyuki Kondo

Mineyuki Yamaga

Tatsuya Imaizumi

Hideo Koizumi

Shigeharu Nishino

Hiroyasu Ota

Yuuji Fujimoto

Hashimoto, Masahiro

The present invention provides a silicon nitride sintered body comprising a silicon nitride crystalline particle and a grain boundary phase, the silicon nitride sintered body having an area ratio of the grain boundary phase per 100 &#x3bc;m&#xd7;100 &#x3bc;m unit area of 15 to 35% when an arbitrary cross section thereof is photographed. Further, it is preferable that the area ratio of the grain boundary phase per 100 &#x3bc;m&#xd7;100 &#x3bc;m unit area is 15 to 25%. Furthermore, the silicon nitride sintered body is suitable for a wear resistant member. Due to above structure, there can be provided a silicon nitride sintered body and a wear resistant member having a high processability (workability) and an excellent sliding property.

Silicon nitride sintered body and wear resistant member using the same

A ceramic-metal composite includes a ceramic substrate, an active metal brazing alloy layer, and a metal plate bonded to the ceramic substrate through the active metal brazing alloy layer disposed therebetween. The active metal brazing alloy layer contains a transition metal that is at least one element selected from Group-8 elements specified in the periodic table. According to the above configuration, the following composite and device can be provided: the ceramic-metal composite that exhibits high bonding strength, heat cycle resistance, durability, and reliability even if the ceramic-metal composite is used in a power module and a semiconductor device including the ceramic-metal composite.

Ceramic metal composite and semiconductor device using the same

A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 &#x3bc;m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball ().

Silicon nitride sintered compact and sliding member using the same

The high thermal conductive aluminum nitride sintered body according to the present invention has: a thermal conductivity of 220 W/m&#xb7;K or more; and a three point bending strength of 250 MPa or more; wherein a ratio (I/I) of X-ray diffraction intensity (I) of AlYO(201 plane) with respect to X-ray diffraction intensity (I) of aluminum nitride (101 plane) is 0.002 to 0.03. According to the foregoing structure, there can be provided an aluminum nitride sintered body having a high thermal conductivity and excellent heat radiating property.

High thermally conductive aluminum nitride sintered product

A silicon nitride abrasion resistant member is formed of silicon nitride sintered body containing 2% to 4% by mass of a rare earth element in terms of oxide thereof as a sintering aid, 2% to 6% by mass of an Al component in terms of oxide thereof, and 2% to 7% by mass of silicon carbide. The silicon nitride sintered body has a porosity of 1% or less, a three-point bending strength of 800 to 1000 MPa, and a fracture toughness of 5.7 to 6.5 MPa&#xb7;m. According to this structure, even when an inexpensive silicon nitride powder manufactured by metal nitriding method is used, there can be provided a silicon nitride abrasion resistant member having a mechanical strength, high abrasion resistance, and a rolling life, equal to or higher than those of conventional silicon nitride sintered bodies, and excellent workability, and a method for manufacturing the member can be provided.

Wear resistant member comprised of silicon nitride and process for producing the same

A silicon nitride sintered body exhibiting a high heat conductivity, the silicon nitride sintered body includes a rare earth element in an amount of 2 to 17.5 mass % in terms of the oxide thereof, Fe in an amount of 0.07 to 0.5 mass % in terms of the oxide thereof, Ca in an amount of 0.07 to 0.5 mass % in terms of the oxide thereof, Al in an amount of 0.1 to 0.6 mass % in terms of the oxide thereof, Mg in an amount of 0.3 to 4 mass % in terms of the oxide thereof, and Hf in an amount not larger than 5 mass % (including 0 mass %) in terms of the oxide thereof.

Silicon nitride sintered body having high heat conductivity and silicon nitride structural element

A silicon nitride wear resistant member is composed of a ceramic sintered body containing 55 to 75 mass % of silicon nitride, 12 to 28 mass % of silicon carbide, 3 to 15 mass % of at least one element selected from the group consisting of Mo, W, Ta, and Nb in terms of silicide thereof, and 5 to 15 mass % of grain boundary phase composed of a rare earth element-Si&#x2014;Al&#x2014;O&#x2014;N, the wear resistant member having an electrical resistance of 10to 10&#x3a9;&#xb7;cm, a porosity of 1% or less, and a three point bending strength of 900 MPa or more. The wear resistant member has a predetermined electric resistance (electro-conductivity) in addition to the high strength and toughness inherent in silicon nitride per se, especially has a high sliding characteristic. Also, a method of manufacturing the wear resistant member is provided.

Silicon nitride anti-wear member and process for producing the same

The present invention provides a wear resistant member composed of silicon nitride sintered body containing 2&#x2013;10 mass % of rare earth element in terms of oxide thereof as sintering agent, 2&#x2013;7 mass % of MgAlOspinel, 1&#x2013;10 mass % of silicon carbide, and 5 mass % or less of at least one element selected from the group consisting of Ti, Zr, Hf, W, Mo, Ta, Nb and Cr in terms of oxide thereof, wherein a porosity of said silicon nitride sintered body is 1 vol. % or less, a three-point bending strength is 900 MPa or more, and a fracture toughness is 6.3 MPa&#xb7;mor more. According to the above structure of the present invention, there can be provided a silicon nitride wear resistant member and a method of manufacturing the member having a high strength and a toughness property, and particularly excellent in rolling and sliding characteristics.

Wear-resistant silicon nitride member and method of manufacture thereof

Wear resistant member comprises a silicon nitride sintered body. Silicon nitride sintered body contains from 75 to 97% by mass of silicon nitride, from 0.2 to 5% by mass of titanium nitride and from 2 to 20% by mass of a grain boundary phase essentially containing Si&mdash;R&mdash;Al&mdash;O&mdash;N compound (R: rare earth element). Particles of titanium nitride are 1 &mgr;m or less in long axis. Particles of titanium nitride are mainly spherical particles of which aspect ratio is in the range of from 1.0 to 1.2, surface thereof being formed edgeless and roundish. Wear resistant member formed of such silicon nitride sintered body is excellent in strength, fracture toughness and rolling fatigue life. In particular, being excellent in rolling fatigue life, it is suitable for bearing member such as bearing balls.

Silicon nitride wear resistant member and manufacturing method thereof

The present invention provides a silicon nitride wear resistant member composed of silicon nitride sintered body containing 1-10 mass % of rare earth element in terms of oxide thereof as sintering agent, wherein a total oxygen content of the silicon nitride sintered body is 6 mass % or less, a porosity of the silicon nitride sintered body is 0.5 vol. % or less, and a maximum size of pore existing in grain boundary phase of the silicon nitride sintered body is 0.3 &mgr;m or less. According to the above structure of the present invention, there can be provided a silicon nitride wear resistant member and a method of manufacturing the member having a high strength and a toughness property, and particularly excellent in sliding characteristics.

Silicon nitride wear resistant member and method of manufacturing the member

Wear resistant member for electronic equipment comprises a silicon nitride sintered body that contains conductivity enhancing particles, and has electrical resistivity in the range from 1 to 10 &OHgr;&middot;m. In silicon nitride sintered body, agglomeration of conductivity enhancing particles in which distance between conductivity enhancing particles is less than 1 &mgr;m exists by 30% or less by area ratio per unit area. Wear resistant member is used for a bearing ball or the like, being applied in a rotation actuator of electronic equipment such as a magnetic recorder and optical disk drive. Malfunction of electronic equipment due to static electricity may be cancelled due to electrical resistivity that silicon nitride sintered body has.

Wear resistant member for electronic equipment, and bearing and spindle motor therewith

The present invention provides a silicon nitride ceramic substrate composed of a silicon nitride sintered body in which maximum size of pore existing in grain boundary phase of the sintered body is 0.3 &mgr;m or less, and having a thermal conductivity of 50 W/mK or more and a three point bending strength of 500 MPa or more, wherein a leak current is 1000 nA or less when an alternative voltage of 1.5 kV-100 Hz is applied to a portion between front and back surfaces of the silicon nitride sintered body under conditions of a temperature of 25&deg; C. and a relative humidity of 70%. According to the above structure of the present invention, there can be provided a silicon nitride ceramic substrate capable of effectively suppressing a leak current generation when the above substrate is assembled into various power modules and circuit boards, and capable of greatly improving insulating property and operative reliability of power modules in which output power and capacity are greatly increased.

Silicon nitride ceramic substrate, silicon nitride ceramic circuit board using the substrate, and method of manufacturing the substrate

Wear resistant member for electronic equipment comprises a zirconium oxide sintered body of which specific resistance is in the range from 1 to 10 &OHgr;&middot;m. A conductivity enhancer of which specific resistance is 10 &OHgr;&middot;m or less is compounded to a zirconium oxide sintered body to materialize specific resistance from 1 to 10 &OHgr;&middot;m. For a conductivity enhancer, carbides and nitrides of various kinds of metals can be used. Wear resistant member can be used as a bearing ball, being applied in a rotational driver of electronic equipment such as a magnetic recording device and an optical disk device. Deficiency due to static electricity of electronic equipment is cancelled due to specific resistance that a zirconium oxide sintered body has.

Wear resistant member for electronic equipment and bearing and spindle motor therewith

A high thermal conductive silicon nitride sintered body of this invention is characterized by containing: 2.0 to 17.5% by weight of a rare earth element in terms of the amount of an oxide thereof; 0.3 to 3.0% by weight of Mg in terms of the amount of an oxide thereof; if necessary, at most 1.5% by weight of at least one of calcium (Ca) and strontium (Sr) in terms of an oxide thereof, if necessary at most 1.5% by weight of at least one element selected from the group consisting of Ti, Zr, V, Nb, Ta, Cr, Mo and W in terms of the amount of an oxide thereof, and at most 0.3% by weight of Al, Li, Na, K, Fe, Ba, Mn and B as impurity cationic elements in terms of total amount thereof, comprising a silicon nitride crystal and a grain boundary phase. The sintered body has a ratio of a crystal compound phase formed in the grain boundary phase to the entire grain boundary phase of at least 20%, a porosity of at most 2.5% by volume, a thermal conductivity of at least 70 W/m&middot;K, and a three-point bending strength of at least 700 MPa at a room temperature. In addition, the sintered body has a small surface roughness even if the sintered body is not subjected to a grinding work, and exhibits an excellent strength characteristics.

High thermal conductive silicon nitride sintered body and method of producing the same

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Yokohama, Japan

Michiyasu Komatsu