Toshiba Materials Co., Ltd.

Kabushiki Kaisha Toshiba

Osaka University

Kai Funaki

Yutaka Abe

Isao Ikeda

Masahiro Kato

Hidetoshi Fujii

Yoshiaki Morisada

Katsuyuki Aoki

Haruhiko Yamaguti

Michiyasu Komatsu

Takayuki Fukasawa

Minoru Takao

Shoya Sano

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 silicon nitride sintered body includes a silicon nitride crystal grains and grain boundary phases. Further, when D stands for width of the silicon nitride sintered body before being subjected to surface processing, relations between an average grain diameter dA and an average aspect ratio rA of the silicon nitride crystal grain in a first region from an outermost surface to a depth of 0 to 0.01D and an average grain diameter dB and an average aspect ratio rB of the silicon nitride crystal grain in a second region inside the first region satisfy the inequalities:0.8≤dA/dB≤1.2; and0.8≤rA/rB≤1.2.

Silicon nitride sintered body, wear-resistant member using the same, and method for producing silicon nitride sintered body

A friction stir welding tool member according to the present embodiment has a shoulder portion and a probe portion concentrically projecting from an upper surface of the shoulder portion. The shoulder portion includes a curved surface processed portion that is curved to have a curved shape on an outer peripheral edge of the shoulder portion. A space occupancy occupied by the two-dimensional space in which neither the shoulder portion nor the probe portion exists is in a range of 30% to 70%, the space occupancy being determined based on a projection drawing of a side surface region surrounded from a tip of the probe portion to the curved surface processed portion of the shoulder portion.

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

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

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.

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Kanagawa, Japan

Kai Funaki