Kyocera Corporation

Nikon Corporation

Honda Motor Co., Ltd.

Shoji Kohsaka

Masahiro Sato

Hideki Uchimura

Hiroshi Aida

Kenichi Tajima

Koichi Tanaka

Shoji Yamashita

Yoshihisa Sechi

Takashi Ono

Yutaka Hayashi

Masaki Terazono

Yumiko Itoh

Masahito Nakanishi

Takehiro Oda

Sentaro Yamamoto

Kazuto Matsukami

Masato Nishihara

Nobuoki Takagi

Akira Saito

Kazunori Koga

Kazumi Osamura

Hitoshi Matsunosako

Hiroshi Maruyama

Yasuharu Tateyama

Toshiaki Shigeoka

Hidemi Matsumoto

Yukiyasu Aoyama

Tomohiro Iwaida

Naoya Fujita

Yoshinori Hirano

Senri Tsujitake

Yusuke Nishikawa

A semiconductive ceramic member according to the present disclosure contains a plurality of aluminum oxide crystal grains, and a plurality of titanium oxide crystal grains. The total content of aluminum oxide and titanium oxide is 99% by mass or more per 100% by mass of all constituents. The content of the aluminum oxide is 86% by mass or more and 96% by mass or less and the content of the titanium oxide is 4% by mass or more and 14% by mass or less per 100% by mass of the aluminum oxide and the titanium oxide in total. A peak of TiO(0<x<2) is present within a binding energy range of 456 eV to 462 eV (both inclusive) in X-ray photoelectron spectroscopy measurement. The semiconductive ceramic member further contains silicon, and the content of the silicon in terms of its oxide in a first region is larger than the content of the silicon in terms of its oxide in a grain boundary.

Semiconductive ceramic member

A fuel cell comprising a gas-permeable and electrically conducting support substrate having a fuel gas passage formed therein; a fuel-electrode layer formed on said substrate; a solid electrolytic layer formed on said support substrate so as to cover said fuel-electrode layer and containing ZrOin which rare earth elements are existing in the form of solid solutions; and an oxygen-electrode provided on the solid electrolytic layer so as to face said fuel-electrode layer; wherein said support substrate is formed of a metal of the iron family and/or an oxide of a metal of the iron family, and a rare-earth oxide containing at least one kind of element selected from the group consisting of Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm and Pr. The invention brings a coefficient of thermal expansion of the support substrate close to that of the solid electrolytic layer, and prevents a reduction in the performance of the solid electrolyte caused by the diffusion of elements from the support substrate.

Fuel cell

A solid oxide fuel cell comprising an electrically conducting electrode-support substrate, an inner electrode layer, a solid electrolyte layer, an outer electrode layer and an interconnector, wherein said electrode-support substrate includes a flat plate having two flat surfaces which are in parallel with each other and forming a plurality of gas flow passages therein, and curved portions located at both ends of said flat plate, and said outer electrode layer is laminated on the solid electrolyte layer so as to be opposed to the other surface of said flat plate where the interconnector is not provided but so as not to be opposed to said curved portions. The solid oxide fuel cell features a small voltage drop, an increased output density, and is easily produced exhibiting stable characteristics.

Low thermal expansion ceramics contains a cordierite crystal phase, wherein a phase of a crystalline compound containing at least one element selected from the group consisting of an alkaline earth element other than Mg, a rare earth element, Ga and In, is precipitated in the grain boundaries of said crystal phase, said ceramics has a relative density of not smaller than 95%, a coefficient of thermal expansion of not larger than 1&#xd7;10/&#xb0; C. at 10 to 40&#xb0; C., and a Young's modulus of not smaller than 130 GPa. That is, the ceramics has a small coefficient of thermal expansion, is deformed very little depending upon a change in the temperature, has a very high Young's modulus and is highly rigid and is resistance against external force such as vibration. Accordingly, the ceramics is very useful as a member for supporting a wafer or an optical system is a lithography apparatus that forms high resolution circuit patterns on a silicon wafer.

Ceramic sintered product and process for producing the same

Low thermal expansion ceramics contains a cordierite crystal phase, wherein a phase of a crystalline compound containing at least one element selected from the group consisting of an alkaline earth element other than Mg, a rare earth element, Ga and In, is precipitated in the grain boundaries of said crystal phase, said ceramics has a relative density of not smaller than 95%, a coefficient of thermal expansion of not larger than 1&times;10,/&deg; C. at 10 to 40&deg; C., and a Young's modulus of not smaller than 130 GPa. That is, the ceramics has a small coefficient of thermal expansion, is deformed very little depending upon a change in the temperature, has a very high Young's modulus and is highly rigid and is resistance against external force such as vibration. Accordingly, the ceramics is very useful as a member for supporting a wafer or an optical system is a lithography apparatus that forms high resolution circuit patterns on a silicon wafer.

This invention relates to a corrosion-resistant member used in a region in which a gas or a plasma of a halogen-containing compound is used, in a process for producing semiconductors, especially a member used as jigs such as a supporter for supporting a material to be treated, or as an inner wall member in an apparatus for producing semiconductors, which has a high corrosion resistance to a fluorine type or a chlorine type corrosive gas, or a fluorine type or a chlorine type plasma. According to this invention, there are provided a corrosion-resistant member to be used ina region in which a gas or plasma of a halogen compound is used in a process of producing a semiconductor, wherein at least surface exposed to the gas or plasma is formed of a boron carbide sintered body having a relative density of at least 96% and containing 300 ppm or below, in a total amount, of an alkali metal, an alkalin earth metal and a transition metal, and a process for producing the same.

Corrosion-resistant member

A dielectric material having a low dielectric loss factor for high-frequency use, which comprises a sintered product of silicon nitride chiefly composed of silicon nitride and containing at least oxygen as an impurity component or oxygen as an impurity component and a compound of an element of the Group 3a of periodic table, wherein said sintered product contains aluminum in an amount which is not larger than 2% by weight reckoned as an oxide thereof having relative densities of not smaller than 97% and has a dielectric loss factor at 10 GHz ofnot larger than 5.times.10.sup.-4. The dielectric material has excellent mechanical properties such as large strength and excellent chemical stability, features small dielectric loss factor in high-frequency regions, and is suited for use as a material for high-frequency oscillators, antennas, filters and electronic circuit boards. In particular, those dielectric materials are suited for use as window materials for introducing high frequencies in a high-frequency plasma-generating CVD apparatus, a microwave wave output unit and an oscillator.

Dielectric material having a low dielectric loss factor for

A sintered product of silicon nitride containing not smaller than 70 mol % of a .beta.-silicon nitride as well as an element of the Group 3a at least including Lu of periodic table and impurity oxygen, wherein when the content of the element of the Group 3a of periodic table and the content of the impurity oxygen are, respectively, expressed being reckoned as the amount of an oxide of the element of the Group 3a of periodic table (RE.sub.2 O.sub.3) and as the amount of SiO.sub.2 of impurity oxygen, their total amount is from 2 to 30 mol %, the molar ratio (SiO.sub.2 /RE.sub.2 O.sub.3) of the amount of the element of the Group 3a of periodic table reckoned as the oxide (RE.sub.2 O.sub.3) thereof to the amount of impurity oxygen reckoned as SiO.sub.2 is from 1.6 to 10, and the intergranular phase of the sintered product chiefly comprises a crystal phase consisting of the element of the Group 3a of periodic table, silicon and oxygen and a process for producing the same. The sintered product has a large strength from room temperature through up to high temperatures and maintains excellent resistance against oxidation even at high temperatures, and exhibits excellent resistance against creeping and excellent breaking toughness.

Sintered product of silicon nitride

A cutting tool composed of silicon nitride comprising chiefly a .beta.-silicon nitride crystal phase and containing a grain boundary phase of rare earth elements, silicon, aluminum, oxygen and nitrogen, wherein the cutting surface is constituted by at least a fired surface or a surface formed by removing and polishing the fired surface by an amount of not larger than 10 .mu.m, and has in the mirror surface thereof a micro-Vicker's hardness which is higher than that of the interior thereof and is not smaller than 16 GPa. The cutting tool has a cutting surface that can be easily worked enabling the cost of working to be decreased, and has a highly hard layer that is suited for cutting cast iron and the like materials featuring increased durability and extended cutting life.

Cutting tool composed of silicon nitride

Disclosed is a silicon nitride sintered body comprising 70 to 99 mole % of silicon nitride, 0.1 to 5 moles % of a rare earth element oxide and up to 25 moles % of silicon oxide and having a silicon oxide-to-rare earth element oxide molar ratio of from 2 to 25, wherein silicon nitride crystal grains have a fine acicular structure having an average particle major axis of up to 7 .mu.m and an average aspect ratio of at least 3.

Silicon nitride sintered body and process for preparation thereof

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Kokubu, Japan

Shoji Kohsaka