National Institute of Advanced Industrial Science and Technology

Agency of Industrial Science and Technology

Denki Kagaku Kogyo Kabushiki Kaisha

Ministry of International Trade & Industry

Agency of Industrial Science and Technology Ministry of International

Nippon Soken, Inc.

Denso Corpora Tion

Shuzo Kanzaki

Kiyoshi Hirao

Shuji Sakaguchi

Suzuya Yamada

Yukihiko Yamauchi

Manuel E Brito

Kazuhiko Koike

Tomohiko Nakanishi

Hideki Kita

Takumi Suzawa

Fumihiro Wakai

Tatsuki Ohji

Naoki Kondo

Shunkichi Ueno

Jayaseelan Daniel Doni

Masaki Yasuoka

The present invention provides a needle-shaped ceramic body and needle-shaped ceramic catalyst body in which a base material is a high specific surface area porous cordierite body that is stable at high temperatures, and also provides methods of producing this needle-shaped ceramic body and needle-shaped ceramic catalyst body. The present invention relates to a needle-shaped ceramic body and needle-shaped ceramic catalyst body in which a base material is a high temperature-stable, high specific surface area porous cordierite body comprising a porous structure having a prescribed porosity and formed of a needle-shaped cordierite crystal phase, and further relates to methods of producing this needle-shaped ceramic body and needle-shaped ceramic catalyst body, and by using porous cordierite constituted of needle-shaped crystals as a catalyst-supporting honeycomb structure, the present invention is able to inhibit sintering-induced reduction in the specific surface area. Since a honeycomb can be directly produced as the cordierite sinter itself, an inexpensive product can be provided through the simplifying the prior-art step of coating the interior of the honeycomb.

Needle-shaped ceramic body, needle-shaped ceramic catalyst body and method for producing same

A boron carbide based sintered body having a four-point flexural strength of at least 400 MPa and a fracture toughness of at least 2.8 MPa&#xb7;m, which has the following two preferred embodiments. (1) A boron carbide-titanium diboride sintered body obtained by sintering a mixed powder of a BC powder, a TiOpowder and a C powder while reacting them under a pressurized condition and comprising from 95 to 70 mol % of boron carbide and from 5 to 30 mol % of titanium diboride, wherein the boron carbide has a maximum particle diameter of at most 5 &#x3bc;m. (2) A boron carbide-chromium diboride sintered body containing from 10 to 25 mol % of CrBin BC, wherein the sintered body has a relative density of at least 90%, boron carbide particles in the sintered body have a maximum particle diameter of at most 100 &#x3bc;m, and the abundance ratio (area ratio) of boron carbide particles of from 10 to 100 &#x3bc;m to boron carbide particles having a particle diameter of at most 5 &#x3bc;m, is from 0.02 to 0.6.

Boron carbide based sintered compact and method for preparation thereof

A method for the production of a high-strength high-toughness silicon nitride sinter includes the steps of mixing a silicon nitride powder with a sintering additive, adding to the resultant mixture as seed particles 0.1 to 10% by volume, based on the amount of the mixture, of elongated single crystal .beta.-silicon nitride particles having a larger minor diameter than the average particle diameter of the silicon nitride powder and having an aspect ratio of at least 2, forming the resultant mixture so as to orient the elongated single crystal .beta.-silicon nitride particles as seed particles in a specific direction, and heating the green body to density it and simultaneously induce epitaxial growth of single crystal .beta.-silicon nitride particles, and a high-strength, high-toughness silicon nitride sinter obtained by the method.

High-strength, high-toughness silicon nitride sinter

Method for producing a high-strength, high-toughness silicon nitride

A sintered ceramic article formed mainly of alumina, having a chemical composition of from 1 to 10% by weight of La.sub.2 O.sub.3, from 0.01 to 0.1% by weight of SiO.sub.2, and the balance of Al.sub.2 O.sub.3 and containing these components in the form of corundum (.alpha.-Al.sub.2 O.sub.3) and lanthanum .beta.-alumina (La.sub.2 O.sub.3.llAl.sub.2 O.sub.3) and a method for the production of a sintered ceramic article formed mainly of alumina, comprising the steps of shaping a mixture of Al.sub.2 O.sub.3, La.sub.2 O.sub.3, and SiO.sub.2, calcining the shaped mixture in the air at a temperature in the range of from 600.degree. C. to 1000.degree. C., and further firing the calcined shaped mixture to a temperature in the range of from 1400.degree. C. to 1800.degree. C.

Sintered ceramic article formed mainly of alumina

A shaped article of superplastic ceramic composed of zirconia toughened ceramic containing, or not containing, fine alumina powder is produced by deforming the ceramic under the action of stress at a temperature in the range of superplastic temperatures thereof.

Method for molding superplastic ceramic

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Nagoya, Japan

Shuzo Kanzaki