Abstract: 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—R—Al—O—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.

Abstract: 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.

Abstract: 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 105 &OHgr;·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.

Abstract: 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° 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.

Abstract: Wear resistant member for electronic equipment comprises a zirconium oxide sintered body of which specific resistance is in the range from 1 to 105 &OHgr;·m. A conductivity enhancer of which specific resistance is 10−5 &OHgr;·m or less is compounded to a zirconium oxide sintered body to materialize specific resistance from 1 to 105 &OHgr;·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.

Abstract: 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.

Abstract: 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 105 &OHgr;·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.

Abstract: 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° 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.

Abstract: Wear resistant member for electronic equipment comprises a zirconium oxide sintered body of which specific resistance is in the range from 1 to 105 &OHgr;·m. A conductivity enhancer of which specific resistance is 10−5 &OHgr;·m or less is compounded to a zirconium oxide sintered body to materialize specific resistance from 1 to 105 &OHgr;·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.

Abstract: 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—R—Al—O—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.

Abstract: 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.

Abstract: There is provided a semiconductor module which comprises a high thermal conductive silicon nitride substrate 10 having a thermal conductivity of 60 w/m·k or more, a semiconductor element 7 mounted on this high thermal conductive silicon nitride substrate 10, metal circuit plates 3 which are bonded on the semiconductor element-mounted side of this high thermal conductive silicon nitride substrate 10 and single metal plate 4a which is bonded to a side opposing to the semiconductor element-mounted side of this high thermal conductive silicon nitride substrate and is bonded on an apparatus casing 9 or a mounting board. By this constitution, there can be provided a semiconductor module having a simple structure, which can be miniaturized, and having an improved structure strength and an excellent heat cycle resistance property without requiring a heat sink plate or the like.

Abstract: This invention provides a silicon nitride circuit board in which a metal circuit plate is bonded to a high thermal conductive silicon nitride substrate having a thermal conductivity of not less than 60 W/m K, wherein a thickness D.sub.S of the high thermal conductive silicon nitride substrate and a thickness D.sub.M of the metal circuit plate satisfy a relational formula D.sub.S .ltoreq.2D.sub.M. The silicon nitride circuit board is characterized in that, when a load acts on the central portion of the circuit board which is held at a support interval of 50 mm, a maximum deflection is not less than 0.6 mm until the silicon nitride substrate is broken. The silicon nitride circuit board is characterized in that, when an anti-breaking test is performed to the circuit board which is held at a support interval of 50 mm, an anti-breaking strength is not less than 500 MPa.

Abstract: This invention provides a silicon nitride circuit board in which a metal circuit plate is bonded to a high thermal conductive silicon nitride substrate having a thermal conductivity of not less than 60 W/m K, wherein a thickness D.sub.s of the high thermal conductive silicon nitride substrate and a thickness D.sub.M of the metal circuit plate satisfy a relational formula D.sub.s .ltoreq.2D.sub.M. The silicon nitride circuit board is characterized in that, when a load acts on the central portion of the circuit board which is held at a support interval of 50 mm, a maximum deflection is not less than 0.6 mm until the silicon nitride substrate is broken. The silicon nitride circuit board is characterized in that, when an anti-breaking test is performed to the circuit board which is held at a support interval of 50 mm, an anti-breaking strength is not less than 500 MPa.

Abstract: This invention provides a silicon nitride circuit board in which a metal circuit plate is bonded to a high thermal conductive silicon nitride substrate having a thermal conductivity of not less than 60 W/m K, wherein a thickness D.sub.s of the high thermal conductive silicon nitride substrate and a thickness D.sub.M of the metal circuit plate satisfy a relational formula D.sub.s .ltoreq.2D.sub.M. The silicon nitride circuit board is characterized in that, when a load acts on the central portion of the circuit board which is held at a support interval of 50 mm, a maximum deflection is not less than 0.6 mm until the silicon nitride substrate is broken. The silicon nitride circuit board is characterized in that, when an anti-breaking test is performed to the circuit board which is held at a support interval of 50 mm, an anti-breaking strength is not less than 500 MPa.

Abstract: The aluminum nitride sintered body according to the present invention comprises 1-10 % by weight of at least one element selected from a group consisting of a group IIIa element listed in periodic table, Ca, Sr and Ba in terms of the amount of an oxide thereof, 0.2-2.0 % by weight of boron carbide, at most 0.2 % by weight of at least one silicon compound selected from a group consisting of SiO.sub.2, Si.sub.3 N.sub.4, SiC, Si.sub.2 N.sub.2 O,.beta.-Sialon, .alpha.-Sialon and poly-type aluminum nitride (Al--Si--O--N) in terms of the amount of Si component, and the balance of aluminum nitride.

Abstract: The present invention provides an aluminum nitride sintered body made by being sintered at a low temperature of 1650.degree. C. or less comprises 0.5 to 7 wt % of oxide of at least one element selected from Group IIIa elements in the periodic table, 0.5 to 3 wt % of calcium oxide, 1.5 wt % or less of aluminum oxide, 0.2 to 1 wt % of glass frit, 0.5 wt % or less of at least one selected from lithium oxide, manganese oxide, chromium oxide, zirconium oxide, strontium oxide and titanium oxide, 1 wt % or less of tungsten in terms of oxide thereof and the balance being aluminum nitride. Calcium tungstate may be contained in an amount of 1 to 3 wt % in place of calcium oxide and tungsten. Further, the aluminum nitride sintered body may be arranged to contain 0.1 to 0.5 wt % of boron oxide, 0.05 to 0.2 wt % of sodium oxide and 0.05 to 0.2 wt % of potassium oxide in place of glass frit.

Abstract: A high thermal conductive silicon nitride sintered body of this invention is characterized by containing more than 7.5 wt % to at most 17.5 wt % of a rare earth element in terms of the amount of an oxide thereof, if necessary, at most 1.0 wt % of at least one of aluminum nitride and alumina, if necessary, 0.1-3.0 wt % of at least one compound selected from the group consisting of oxides, carbides, nitrides, silicides and borides of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and at most 0.3 wt % of Li, Na, K, Fe, Ca, Mg, Sr, Ba, Mn and B as impurity cationic elements in terms of total amount thereof, containing a .beta.-type silicon nitride crystal and a grain boundary phase. The sintered body has a ratio of a crystal compound phase 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 80 W/m.multidot.K and a three-point bending strength of at least 650 MPa at a room temperature.

Abstract: A high thermal conductive silicon nitride structural member of the present invention contains a rare earth element in the range of 1.0 to 7.5 wt. % calculated as oxide thereof and Li, Na, K, Fe, Ca, Mg, Sr, Ba, Mn and B as impurity cationic elements in a total amount not greater than 0.3 wt. %, and has the thermal conductivity not less than 60 W/(m.K), preferably not less than 80 W/(m.K). Also, a high thermal conductive silicon nitride sintered body consists of silicon nitride particles and a grain boundary phase, a crystal compound phase in the grain boundary phase being not less than 20 vol. %, preferably not less than 50 vol. %, with respect to the entire grain boundary phase, and has the thermal conductivity not less than 60 W/(m.K), preferably not less than 80 W/(m.K).

Abstract: A silicon nitride-based sinter contains as component elements thereof magnesium in the range of from 0.1 to 1.5% by weight, aluminum in the range of from 0.1 to 3.5% by weight, carbon in the range of from 0.01 to 6% by weight, and oxygen in the range of from 0.2 to 5% by weight, the balance consisting essentially of silicon, nitrogen, and impurities. This sinter is obtained by sintering a ceramic mixture comprising 0.5 to 6% by weight of a MgO.Al.sub.2 O.sub.3 spinel structure, 0.1 to 20% by weight of silicon carbide, not more than 1% by weight of silicon oxide, and the balance substantially of silicon nitride and impurities. Owing to the incorporation of the MgO.Al.sub.2 O.sub.