Other

Sumitomo Electric Industries, Limited

Matsushita Electric Works, Ltd.

The Research Institute for Iron, Steel and Other Metals of the Tohoku

Ngk Insulators, Inc.

Mitsubishi Materials Corporation

Fine Ceramics Research Association

Denso Corporation

Mitsubishi Gas Chemical Company, Inc.

Agency of Industrial Science and Technology

Kabushiki Kaisha Riken

Noritake Co., Ltd.

Japan as Represented by Director General of Agency of Industrial Science

Mitsubishi Mining and Cement Co. Ltd.

Nagaoka University of Technology

Koichi Niihara

Masahiro Nawa

Tohru Sekino

Shoichi Nakamoto

Takashi Koyama

Akira Yamakawa

Hiroshi Sasaki

Yuji Katsuda

Masashi Yoshimura

Yoshimasa Kobayashi

Toshio Hirai

Mutsuo Sando

Jun Hasegawa

Hiroaki Sakai

Atsushi Nakahira

Miho Ito

Atsuya Towata

Hisao Ueda

Keiichi Yamasaki

Tadachika Nakayama

Takamasa Kawakami

Tetsuo Uchiyama

Misao Iwata

Keiichi Yamazaki

Kansei Izaki

Kenji Oshima

Hae Jin Hwang

Masaki Yasuoka

Yoshitsugu Kato

Ryuichi Matsuki

Takeyoshi Takenouchi

Manwar Hussain

Toru Nagai

Yong-Ho Choa

Kotaro Kawahara

Sigeo Inoue

Hiroshi Nishida

Yoshiyuki Hamahashi

Tsugio Ito

A catalyst assembly comprising a substrate, nanofilaments which have a nanometer-size diameter and are formed on the substrate, and particles which have a nanometer-size diameter, at least one of the nanofilaments and the particles having a catalytic function, is provided to use a catalyst more efficiently and to provide a catalytic function more efficiently. Interstices between the nanofilaments serve as distribution channels of a reactive gas, and the reactive gas spreads sufficiently not only around the ends of nanofilaments but also inside a catalyst assembly. A combination of nanofilaments and particles enables dispersion of a catalyst at a distance of not more than about 100 nanometers.

Catalyst assembly

Catalyst particles and method of manufacturing the same

A deformable conductive elastomer excellent in reliability, linearity, and mechanical characteristics, and a manufacturing method thereof are provided. Elastomer particles with a particle size of 10 through 300 &mgr;m and conductive particles with a particle size of 10 through 40 &mgr;m are almost uniformly dispersed in a non-conductive elastomer. Ceramic particles with a particle size of 1000 nm or less are also almost uniformly dispersed in the non-conductive elastomer. At least the non-conductive elastomer uncrosslinked, the elastomer particles, and the conductive particles are added to the dispersion medium, and the mixture is vibrated, mixed, and dried to crosslink the uncrosslinked non-conductive elastomer. At least the non-conductive elastomer, the elastomer particles, and the conductive particles are added to the dispersion medium, and the mixture is vibrated, mixed, and dried.

Deformable conductive elastomer and manufacturing method thereof

The present invention provides a method for the manufacture of ceramic composite fibers, and the present invention relates to a method for the manufacture of a composite fiber in which a second phase is dispersed within a matrix fiber, wherein the matrix consists of a substance selected from alumina, zirconia, mullite, YAG, silica, magnesia, nitrides, carbides, metals, alloys, and polymers; the second phase consists of a substance selected from zirconia, mullite, YAG, and other oxides, or from metals; and the composite fiber is produced by synthesizing a fiber from a precursor solution containing the substance of the matrix, and the starting solution which serves as the second phase, dispersed through the matrix solution, and then heating the fiber.

Method for manufacture of composite fiber

A method for the manufacture of a ceramic composite fiber in which a second phase is dispersed within a matrix fiber, wherein the matrix consists of a substance selected from alumina, zirconia, mullite, YAG, silica, magnesia, nitrides, carbides, metals, alloys, and polymers; the second phase consists of a substance selected from zirconia, mullite, YAG, other oxides, and metals; and the composite fiber can be produced by synthesizing a fiber from a precursor solution containing the substance of the matrix, and the second phase starting solution dispersed through the solution, and then heating the fiber.

Method for manufacture composite fiber

A zirconia based ceramic material having improved and well-balanced mechanical strength and toughness consists essentially of 0.5 to 50 vol % of Al.sub.2 O.sub.3 having an average grain size of 2 .mu.m or less and the balance of a partially stabilized zirconia having an average grain size of 5 .mu.m or less. The partially stabilized zirconia consists essentially of 8 to 12 mol % of CeO.sub.2, 0.05 to 4 mol % of TiO.sub.2 and the balance of ZrO.sub.2. Fine Al.sub.2 O.sub.3 grains having an average grain size of 1 .mu.m or less are dispersed within the grains of the partially stabilized zirconia at a dispersion ratio. The dispersion ratio is defined as a ratio of the number of Al.sub.2 O.sub.3 grains dispersed within the grains of the partially stabilized zirconia relative to the number of the entire Al.sub.2 O.sub.3 grains dispersed in the ceramic material, and at least 2% in the present invention. The ceramic material can be made by the following process. A first constituent formed of the partially stabilized zirconia is mixed with a second constituent formed of Al.sub.2 O.sub.3 to obtain a mixture. The mixture is molded into a desired shape, and then sintered in the air under an atmospheric pressure to obtain the ceramic material.

Process of making zirconia based ceramic material

An object of the present invention is to provide a novel ceramic composite that has not only excellent dynamic characteristics, but also good electromagnetic characteristics, typified by dielectric characteristics, and the present invention relates to a ceramic composite, characterized in that an oxide having a perovskite structure which includes as raw materials lead and/or an alkaline earth metal is dispersed in a ceramic matrix, and in the above-mentioned ceramic composite, preferably the ceramic matrix is MgO, MgAl.sub.2 O.sub.4, or ZrO.sub.2, and also, preferably in the above-mentioned ceramic composite, the perovskite structure oxide particles are covered with MgO, MgAl.sub.2 O.sub.4, or ZrO.sub.2, and the ceramic matrix is Al.sub.2 O.sub.3.

Ceramic composite

A ZrO.sub.2 based ceramic material having excellent mechanical strength and fracture toughness comprises a first phase of ZrO.sub.2 grains containing CeO.sub.2 as a stabilizer and having an average grain size of 5 .mu.m or less, a second phase of Al.sub.2 O.sub.3 grains having an average grain size of 2 .mu.m or less, and a third phase of elongated crystals of a complex oxide of Al, Ce, and one of Mg and Ca. At least 90 vol % of the first phase is composed of tetragonal ZrO.sub.2. An aluminum (Al) content in the ceramic material is determined such that when Al of the complex oxide is converted to Al.sub.2 O.sub.3, a total amount of Al.sub.2 O.sub.3 in the ceramic material is within a range of 0.5 to 50 vol %. A content of the third phase in the ceramic material is determined within a range of 0.5 to 5 by area %. It is preferred that fine Al.sub.2 O.sub.3 grains having an average grain size of 1 .mu.m or less of the second phase are dispersed within the ZrO.sub.2 grains at a dispersion ratio of at least 2%.

ZrO.sub.2 based ceramic material and method of producing the same

A ceramic porous body composed principally of silicon carbide or silicon nitride which has higher strength, higher heat resistance and higher thermal shock resistance and has a large number of fine pores, and a method of producing the same. The ceramic porous body, comprised principally of silicon carbide or silicon nitride, has a pore diameter of not more than 1 .mu.m, with a porosity of not less than 35%, and has a flexural strength of not less than 100 MPa. The ceramic porous body is produced by using a silicon oligomer which is capable of producing silicon carbide or silicon nitride when calcined, mixing the silicon oligomer with a silicon carbide powder or silicon nitride powder, and/or other ceramic powder which has a mean particle diameter of not more than 1.0 .mu.m, molding the mixture into shape, then sintering the molding in a suitable atmosphere at temperatures of not less than 1200.degree. C.

Ceramic porous bodies and method of producing the same

Zirconia based ceramic material

A platelet .alpha.-Al.sub.2 O.sub.3 based ceramic composite consists of Al.sub.2 O.sub.3 powder, promoters and controllers. The composite is prepared by mixing aluminum oxide powder with promoters and controllers. The mixture is shaped and sintered to form an object. In one embodiment of the invention, the promoters are either salts or oxides of alkaline metals and alkaline earth metals. The salts are oxidized during sintering.

Process for producing platelet .alpha.-Al.sub.2 O.sub.3 based ceramic

A process for the production of a sintered composite boron carbide body, the process comprising:

Process for forming a sintered composite boron carbide body

The strength of a composite sintered body including yttrium oxide is improved. A composite ceramics sintered body includes a matrix of yttrium oxide and silicon carbide particles dispersed within the matrix. A compound oxide phase including yttrium and silicon is present at the surface of the sintered body. A sintered body is obtained by compression-molding mixed powder including yttrium oxide powder and silicon carbide powder in an inert gas atmosphere of at least 1550.degree. C. The sintered body is subjected to a heat treatment for at least 0.5 hour and not more than 12 hours in an atmosphere including oxygen gas in the range of at least 900.degree. C. and less than 1200.degree. C.

Method of manufacturing a composite ceramics sintered body

A zirconia based composite material with improved strength and toughness includes a partially stabilized zirconia including 1.5 to 4.5 mol % of yttrium oxide as a matrix thereof and a metal phase of at least one metal selected from the group consisting of titanium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as metal grains dispersed in the matrix. The metal phase has a melting point higher than a sintering temperature of the partially stabilized zirconia. In addition, it is preferred that the composite material further contains a ceramic phase of at least one ceramic selected from the group consisting of Al.sub.2 O.sub.3, SiC, Si.sub.3 N.sub.4, B.sub.4 C, carbides, nitrides and borides of titanium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as ceramic grains dispersed in the matrix. The composite material of the present invention is manufactured by the following steps. A mixture is prepared by incorporating at least one first constituent forming the partially stabilized zirconia with at least one second constituent forming the metal phase, and if necessary, at least one third constituent forming the ceramic phase. The mixture is sintered in a non-oxidation atmosphere to obtain the composite material.

Zirconia based composite material and method of manufacturing the same

Growing community of inventors

Osaka, Japan

Koichi Niihara