Kabushiki Kaisha Toshiba

Toshiba Materials Co., Ltd.

Osaka University

Koyo Seiko Company, Ltd.

Isao Ikeda

Yutaka Abe

Kai Funaki

Michiyasu Komatsu

Masahiro Kato

Hidetoshi Fujii

Yoshiaki Morisada

Minoru Takao

Hisao Yabe

Hiroki Tonai

Yoshiyuki Fukuda

Hiroshi Komorita

Hiroaki Takebayashi

Kazunori Hayashida

Yukihiro Takenami

The friction stir welding tool member according to the present invention is made of a ceramic member in which a shoulder portion and a probe portion are integrally formed, wherein a root portion of the probe portion and an end portion of the shoulder portion have a curved surface shape; and the friction stir welding tool member has a ratio (R1/D) of 0.02 or more and 0.20 or less when a curvature radius of the end portion of the shoulder portion is defined as R1 (mm) and an outer diameter of the shoulder portion is defined as D (mm). In addition, the ceramic member is preferably made of a silicon nitride sintered body having a Vickers hardness of 1400 HV1 or more. According to the above-described configuration, a friction stir welding tool member having excellent durability can be provided.

Friction stir welding tool member, friction stir welding apparatus using the same, and friction stir welding method

The friction stir welding tool member according to the present invention is made of a silicon nitride sintered body, wherein the silicon nitride sintered body contains 15% by mass or less of additive components except silicon nitride in such a manner that the additive components include at least one element selected from lanthanoid elements and at least one element selected from Mg, Ti, Hf, and Mo. In addition, it is preferable that the additive components further include at least one element selected from Al, Si, and C. According to the above-described configuration, a friction stir welding tool member having an excellent durability can be provided.

Friction stir welding tool member made of silicon nitride sintered body, and friction stir welding apparatus using the same

The present invention provides a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, wherein the silicon nitride crystal grains are covered with the grain boundary phase and width of the grain boundary phase is 0.2 nm or more. It is preferable that the width of the grain boundary phase is 0.2 nm to 5 nm. Additionally, it is preferable that the silicon nitride sintered body includes 15% by mass or less of the grain boundary phase. According to the above-described configuration, it is possible to provide a high-temperature-resistant silicon nitride sintered body in which degradation of the grain boundary phase under high temperature environment is suppressed. This silicon nitride sintered body is suitable for constituent material of a high-temperature-resistant member, use environment of which is 300&#xb0; C. or higher.

Silicon nitride sintered body and high-temperature-resistant member using the same

The present invention provides a welding tool member for friction stir welding comprising a silicon nitride sintered body, wherein the silicon nitride sintered body includes an additive component other than silicon nitride in a content of 15% by mass or less, and the additive component includes three or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. It is preferable that the content of the additive component is 3% by mass or more and 12.5% by mass or less. It is also preferable that the additive component includes four or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. Due to above structure, there can be provided a welding tool member for friction stir welding having a high durability.

Friction stir welding tool member made of silicon nitride sintered body and friction stir welding apparatus using same

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.

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

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.3 spinel structure and silicon carbide, the produced silicon nitride-based ceramic acquires an outstanding ability to resist corrosion caused by such chemicals as acids and alkalis (resistance to chemicals) without impairing such inherent characteristic properties of silicon nitride as strength, resistance to abrasion, and resistance to heat.

Silicon nitride-based sinter

Rolling bearing

Sintered ceramic articles and a method for the production thereof are disclosed. When a shaped Si.sub.3 N.sub.4 ceramic article is sintered in the presence of SiO.sub.2 or a SiO.sub.2 -containing substance in an inactive gas atmosphere, there is obtained a sintered ceramic article having the surface thereof coated with a thin layer formed preponderantly of silicon oxynitride (Si.sub.2 N.sub.2 O). The sintered ceramic article of this invention excels in resistance to elevated temperatures, particularly temperatures exceeding 1200.degree. C., and enjoys a good surface condition.

Growing community of inventors

Kanagawa, Japan

Isao Ikeda