Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Other

Nobuyuki Nagato

Kazumi Naito

Kotaro Yano

Masashi Shigeto

Kazuhiro Omori

Hitoshi Ohmori

Yoshimasa Ishimura

Taketoshi Naito

Ryoji Ishioka

Naoki Oyanagi

Kenichiro Maki

Hiroshi Uchida

Hideo Takahashi

Katsumi Murofushi

Yuichi Sugiyama

Yutaka Yamagata

Tetsuhiko Yamaguchi

Teijiro Kitao

Yuseki Suyama

Kunio Imamura

Mitsuhiro Imaizumi

Kunio Komaki

Kuniaki Shimbo

Nobuhide Itoh

Shigehiro Nishino

Isamu Taguchi

Tomoe Uematsu

Hideki Mori

Isamu Yamamoto

Katsura Horikoshi

Takami Oe

Masato Futagami

According to the present invention, a process for producing an epoxy compound, where an epoxy compound can be selectively produced from olefins with good yield at low cost in a safe manner by a simple operation under mild conditions without using a quaternary ammonium salt or a metal compound, is provided. The present invention relates to a process for producing an epoxy compound, comprising epoxidizing a carbon-carbon double bond of an organic compound having a carbon-carbon double bond by using hydrogen peroxide as an oxidant, wherein the epoxidation is carried by out using an organic nitrile compound and an organic amine compound.

Process for producing epoxy compound

A niobium powder for capacitors, which contains niobium monoxide crystal or hexaniobium monoxide crystal; a sintered body thereof; and a capacitor fabricated from the sintered body as one part electrode, a dielectric material formed on the surface of the sintered body, and another part electrode provided on the dielectric material.

Niobium powder for capacitor, sintered body thereof and capacitor using the sintered body

A niobium powder for capacitors, having an average particle size of from 10 to 500 &#x3bc;m, which is a granulated powder having an oxygen content of 3 to 9% by mass; a sintered body thereof; and a capacitor fabricated from the sintered body as one part electrode, a dielectric material formed on the surface of the sintered body, and another part electrode provided on the dielectric material. A capacitor manufactured from the sintered body of a niobium powder of the present invention is prevented from deterioration in the performance for a long period of time and has high reliability.

A powder composition for a capacitor comprising a tantalum or niobium and a compound having a silicon-oxygen bond, at least a part of which may be nitrided and which has an average particle size of from 0.1 to 5 &#x3bc;m; a sintered body using the composition; and a capacitor constituted by the sintered body as one part electrode, and another part electrode. A capacitor favored with high reliability, lower dissipation level of power and smaller deterioration of capacitance than conventional tantalum capacitors using tantalum can be produced by using a sintered body of the powder composition for a capacitor.

Powder composition for capacitor, sintered body using the composition and capacitor using the sintered body

A niobium primary powder having an average particle size of 0.01 to 0.5 &#x3bc;m and an average circular degree of 0.8 or more, the circular degree being defined by 4 &#x3c0;A/L(wherein A is an area of a solid projected on a plain face and L is an outer circumferential length of the projection view); a niobium primary agglomerated powder having an average particle size of 0.03 to 20 &#x3bc;m, which is an agglomerate of the niobium primary powder; a niobium secondary agglomerated powder having an average particle size of 50 to 150 &#x3bc;m, which is obtained by granulating the primary agglomerated powder; a sintered body of the niobium primary agglomerated powder or niobium secondary agglomerated powder; and a capacitor using the sintered body. By using sintered bodies of the niobium primary agglomerated powder or niobium secondary agglomerated powder, a capacitor having a large capacitance per unit volume and good voltage resistance can be manufactured.

Powder for capacitor, sintered body and capacitor using the sintered body

Silicon carbide single crystal is produced by allowing a silicon raw material to continuously react with a carbon raw material to generate gas, which reaches a seed crystal substrate on which a silicon carbide single crystal grows. Preferably, the silicon raw material is continuously fed onto the carbon raw material placed in a reaction crucible, and the carbon raw material is maintained at a temperature such that carbon is allowed to react with silicon in a molten state or a gaseous state to generate the reaction gas. An apparatus used for producing the silicon carbide single crystal comprises a reaction crucible, and a seed crystal substrate disposed in the reaction crucible; and further comprises means for maintaining the carbon raw material placed in the reaction crucible at a temperature such that carbon is allowed to react with silicon in a molten state or a gaseous state to generate the reaction gas, and means for continuously feeding the silicon raw material onto the carbon raw material placed in the reaction crucible.

Method and apparatus for producing silicon carbide single crystal

A niobium powder for capacitors, having an average particle size of from 10 to 500 &mgr;m, which is a granulated powder having an oxygen content of 3 to 9% by mass; a sintered body thereof; and a capacitor fabricated from the sintered body as one part electrode, a dielectric material formed on the surface of the sintered body, and another part electrode provided on the dielectric material. A capacitor manufactured from the sintered body of a niobium powder of the present invention is prevented from deterioration in the performance for a long period of time and has high reliability.

The present invention comprises a metal bond grind stone having a flat plate portion and a tapered portion ; an electrode opposed to the metal bond grind stone with a gap therebetween; voltage applying means for applying a direct-current pulse voltage between the metal bond grind stone and the electrode; conductive liquid supplying means for supplying a conductive liquid between the metal bond grind stone and the electrode; and grind stone moving means for moving the metal bond grind stone in a direction orthogonal to the shaft center thereof, and an ingot of a single crystal SiC is thereby cut at the tapered portion of the metal bond grind stone and the cut surface is then specular-worked at the flat plate portion

Method and apparatus for cutting and grinding single crystal SiC

An object of the present invention is to provide a niobium powder for producing a capacitor exhibiting excellent reliability; a sintered body formed from the powder; and a capacitor including the sintered body. Even when niobium exhibiting high affinity to oxygen is employed, the niobium powder is obtained by regulating the amount of oxygen contained in the powder. By employing niobium powder which has undergone partial oxidation and partial nitridation, in which the mass ratio of the nitrogen content to the oxygen content is about 1/45 or more, a capacitor exhibiting excellent reliability can be obtained.

Niobium powder, sintered body using the powder, and capacitor using the same

A nobium powder for capacitors, which contains from 0.05 to 20% by mass of niobium monoxide crystal and from 0.05 to 20% by mass of hexaniobium monoxide crystal; a sintered body thereof; and a capacitor fabricated from the sintered body as one part electrode, a dielectric material formed on the surface of the sintered body, and another part provided on the dielectric material. A capacitor manufactured from a sintered body of a niobium powder of the present invention is favored with good high-temperature characteristics.

A powder composition for a capacitor comprising a tantalum or niobium and a compound having a silicon-oxygen bond, at least a part of which may be nitrided and which has an average particle size of from 0.1 to 5 &mgr;m; a sintered body using the composition; and a capacitor constituted by the sintered body as one part electrode, and another part electrode. A capacitor favored with high reliability, lower dissipation level of power and smaller deterioration of capacitance than conventional tantalum capacitors using tantalum can be produced by using a sintered body of the powder composition for a capacitor.

A thin strip-shaped grindstone is held flat under tension and moved backwards and forwards in the longitudinal direction, while the grindstone is moved in a direction perpendicular to a cylindrical ingot and cuts the ingot. A metal-bonded grindstone is used as the strip-shaped grindstone at least one pair of electrodes are disposed adjacent to both surfaces of the metal-bonded grindstone one on each side of the ingot. The metal-bonded grindstone is made the positive electrode and DC voltage pulses are applied between the grindstone and the electrodes, and at the same time, a conducting processing fluid is fed to the gaps between the metal-bonded grindstone and the electrodes, and both surfaces of the metal-bonded grindstone are dressed electrolytically on both sides while the cylindrical ingot is being cut by the metal-bonded grindstone. A large diameter, hard, refractory ingot can be efficiently cut with a small amount of cutting waste, warping and uneven thickness of the finished surface are reduced, roughness of the cut surface is small, little damage is given to the crystal during processing, running costs are low and there is a reduction in manpower requirements.

Apparatus and method for cutting ingots

The present invention provides an electrode material for capacitors, capable of ensuring a large capacitance per unit weight without worsening the leakage current property, and a capacitor using the material. The present invention also provides an electrode material for capacitors, obtained by reacting a tantalum metal and/or a niobium metal or an alloy thereof having an oxide film on the surface thereof with an alkali solution to form a tantalic acid compound and/or a niobic acid compound on the surface thereof. Furthermore, the present invention provides a capacitor using the electrode material.

Electrode material for capacitors and capacitor using the same

A powder composition for a capacitor comprising a tantalum or niobium and a compound having a silicon-oxygen bond, at least a part of which may be nitrided and which has an average particle size of from about 0.1 to about 5 &mgr;m; a sintered body using the composition; and a capacitor constituted by the sintered body as one part electrode, and another part electrode. A capacitor favored with high reliability, lower dissipation level of power and smaller deterioration of capacitance than conventional tantalum capacitors using tantalum can be produced by using a sintered body of the powder composition for a capacitor.

Growing community of inventors

Chiba, Japan

Nobuyuki Nagato