Kabushiki Kaisha Toshiba

Toshiba Materials Co., Ltd.

Minoru Takao

Michiyasu Komatsu

Yoshiyuki Fukuda

Isao Ikeda

Hisao Yabe

Hiroki Tonai

Yukihiro Takenami

Katsuyuki Aoki

Hiroshi Komorita

Yutaka Abe

Kai Funaki

Kimiya Miyashita

Katsuhiro Shinosawa

Haruhiko Yamaguti

The sliding member according to the embodiment includes a silicon nitride sintered body that includes silicon nitride crystal grains and a grain boundary phase, in which a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains among any 50 of the silicon nitride crystal grains having completely visible contours in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 10%. The percentage is more preferably not less than 0% and not more than 3%.

Sliding member, and bearing, motor, and drive device using the same

A wear resistant member formed of ceramic sintered body mainly composed of silicon nitride, the ceramic sintered body containing 10 to 3500 ppm of an Fe component in terms of Fe element, more than 1000 ppm to 2000 ppm of a Ca component in terms of Ca element, and 1 to 2000 ppm of a Mg component in terms of Mg element, wherein a &#x3b2;-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 &#x3bc;m or less, Ca component existing in grain boundary phase is not detected by XRD (X-ray Diffraction method), and each of dispersions in Vickers hardness, fracture toughness and density of the wear resistant member is within a range of &#xb1;10%. According to this structure, there can be obtained a wear resistant member comprising a ceramic sintered body improved in grinding-work property in addition to an excellent wear resistant property.

Wear resistant member, and method for manufacturing the wear resistant member

A sliding member includes a silicon nitride sintered compact containing a rare earth element of 7 to 18 mass % in terms of oxide and at least one element M selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W of 0.1 to 3 mass % in terms of oxide, and having a total content of impurity positive ion elements of 0.3 mass % or less and a thermal conductivity of 60 W/m&#xb7;K or higher. The silicon nitride sintered compact includes silicon nitride crystal grains and a grain boundary phase, and has a ratio of crystalline compound phases in the grain boundary phase of 20% or more in area ratio, and an average grain size of the crystalline compound phases of 0.5 &#x3bc;m or less. The sliding member is used, for example, as a bearing ball

Slide member and bearing utilizing the same

A wear resistant member formed of silicon nitride sintered body having a volume of 4000 mmor more, the silicon nitride sintered body containing 1 to 5 mass % of a rare earth component in terms of rare earth element, 1 to 6 mass % of an Al component in terms of Al element, 10 to 3500 ppm of an Fe component in terms of Fe element, and 10 to 1000 ppm of a Ca component in terms of Ca element, wherein a &#x3b2;-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 &#x3bc;m or less, and each of dispersions in Vickers hardness and fracture toughness of an inner portion of the wear resistant member is within a range of &#xb1;10%. According to this structure, the wear resistant member can be manufactured with a low cost, and there can be provided a wear resistant member comprising a silicon nitride sintered body excellent in reliability and the dispersion in characteristics is effectively suppressed.

Wear resistant member, wear resistant device and method for manufacturing the wear resistant member

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

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

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

In material for ceramic ball that has a spherical portion of approximate sphere at both ends thereof and a belt-like portion at a center thereof over an entire circumferential direction, a difference between a diagonal diameter of the belt-like portion and a polar diameter of the spherical portion is 100 &mgr;m or less. A height of the belt-like portion from the spherical portion is preferable to be 1 mm or less. A width of the belt-like portion is preferable to be 5 mm or less. The material for ceramic ball can be used for material for bearing balls for instance. When applying in such a usage, the material for ceramic ball essentially consists of silicon nitride, Vickers hardness thereof being preferable to be 1400 or more. In the material for ceramic ball of the present invention, a difference between a diagonal diameter of a belt-like portion and a polar diameter of a spherical portion is set at 100 &mgr;m or less. As a result, the material is formed in a shape where the belt-like portion does not project from the spherical portion. Thereby, the belt-like portion of the material for ceramic ball and polar diameter of the spherical portion come into average contact with abrasives or the like. Accordingly, different from the case of the existing material, the belt-like portion can be suppressed from wearing and damaging the abrasives due to the contact.

Material for ceramic ball and method of manufacturing ceramic ball

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.

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Yokohama, Japan

Minoru Takao