Shoei Chemical Inc.

Masayuki Maekawa

Yuji Akimoto

Kazuro Nagashima

Hidenori Ieda

Shinichi Ono

Fumiyuki Shimizu

Eiichi Asada

Mineto Iwasaki

Hiroshi Yoshida

Yasuhiro Kamahori

Seiyu Teruya

Kazurou Nagashima

Fujio Amada

Hirotaka Takushima

Junichi Ozawa

Shusaku Kawaguchi

Tomotaka Nishikawa

A method for manufacturing metal powder includes: melting at least a portion of a metal starting material in a reaction vessel by utilizing plasma so as to form molten metal; evaporating the molten metal so as to produce a metal vapor; and transferring the metal vapor from the reaction vessel to a cooling tube together with a carrier gas supplied into the reaction vessel so as to cool the metal vapor, and condensing the metal vapor in the cooling tube, thereby producing metal powder. The method further includes supplying an oxygen gas into the reaction vessel.

Method for manufacturing metal powder

A plasma device for production of metal powder includes a reaction vessel, a plasma torch, a carrier gas supply unit and a cooling tube. A metal starting material is supplied to the vessel. The torch produces plasma between the torch and the metal starting material to evaporate the metal starting material and produce a metal vapor. The supply unit supplies into the vessel a carrier gas for carrying the metal vapor. The cooling tube is provided with indirect and direct cooling sections and cools the metal vapor transferred from the vessel to produce the metal powder. The metal vapor and/or the metal powder are indirectly cooled in the indirect cooling section and directly cooled in the direct cooling section. A projection and/or a recess are disposed at least on a part of an inner wall of the indirect cooling section.

Plasma device for production of metal powder

Fine, highly-crystallized metal powder is produced at low cost and high efficiency by a method involving: ejecting raw material powder composed of one or more kinds of thermally decomposable metal compound powders into a reaction vessel through a nozzle together with a carrier gas and producing a metal powder by heating the raw material powder at a temperature Twhich is higher than the decomposition temperature of the raw material powder and not lower than (Tm&#x2212;200&#xb0;) C. where Tm is the melting point (&#xb0; C.) of the metal to be produced, while allowing the raw material powder to pass through the reaction vessel in a state where the raw material powder is dispersed in a gas phase at a concentration of 10 g/liter or less, wherein an ambient temperature Tof a nozzle opening part is set to a temperature of 400&#xb0; C. or higher and lower than (Tm&#x2212;200&#xb0;) C.

Metal powder production method, metal powder produced thereby, conductive paste and multilayer ceramic electronic component

Metal particles that can be alloyed with rhenium are dispersed as a main component in a gas phase, a rhenium oxide vapor is made to be present around these particles, the rhenium oxide is reduced, and the rhenium precipitated on the surface of the main component metal particles as a result of this reduction is diffused under a high temperature into the main component metal particles, which gives a rhenium-containing alloy powder including the main component metal and rhenium. The powder thus obtained preferably contains 0.01 to 50 wt % rhenium, has an average particle size of 0.01 to 10 &#x3bc;m, and is made into a conductor paste by being uniformly mixed and dispersed in an organic vehicle along with other additives as needed.

Method for manufacturing rhenium-containing alloy powder, rhenium-containing alloy powder, and conductor paste

A method of manufacturing a highly crystallized phosphor powder, comprising: making a raw material solution containing metal elements and/or semimetal elements that will be constituents of the phosphor into fine liquid droplets, subjecting the liquid droplets to decomposition by heating at a temperature of 500 to 1800&#xb0; C. to produce hollow precursor particles and/or porous precursor particles, heating the precursor particles to crystallize the precursor particles while maintaining the hollow or porous form, and grinding the crystallized particles down to a predetermined particle size. The obtained phosphor powder is a high luminance inorganic phosphor powder that is extremely fine, and yet has few defects on the surface of or inside the powder, and hence has excellent crystallinity and light emission characteristics, and provides a phosphor composition useful for producing a phosphor layer with high coverage and high luminance of light emission.

Method of manufacturing phosphor powder, phosphor powder, and phosphor composition

A method in which a metal powder is produced by ejecting a thermally decomposable metal compound powder into a reaction vessel through a nozzle together with a carrier gas under the condition V/S&#x3e;600, where V is the flow rate of the carrier gas per unit time (liter/min), and S is the cross-sectional area of the nozzle opening part (cm), and heating this metal powder at a temperature which is higher than the decomposition temperature of the metal compound powder and not lower than (Tm&#x2212;200)&#xb0; C., where Tm is the melting point of the metal, in a state where the metal compound powder is dispersed in the gas phase at a concentration of 10 g/liter or less. The method provides a fine, spherical, highly-crystallized metal powder which has a high purity, high density, high dispersibility and extremely uniform particle size, at low cost and using a simple process.

A method for preparing a highly crystallized metal powder, involving the steps of: supplying at least one heat-decomposable metal compound powder into a reaction vessel using a carrier gas; and forming a metal powder by heating the metal compound powder in a state in which the metal compound powder is dispersed in a gas phase at a concentration of no more than 10 g/liter, at a temperature that is over the decomposition temperature of the metal compound powder and at least (Tm &minus;200)&deg; C. when the melting point of the metal contained in the metal compound powder is Tm&deg; C. The method provides a high-purity, high-density, highly dispersible, fine, highly crystallized metal powder consisting of spherical particles of uniform size, which is suitable for use in thick film pastes, and particularly conductor pastes and the like used in the preparation of multilayer ceramic electronic parts.

Method for preparing metal powder

An oxidation-resistant palladium powder containing one or more alkaline earth metal elements in a total amount of at least 0.005% by weight relative to Pd. The palladium powder is useful as a conductive component of a thick-film conductive paste and the resultant conductive paste can provide internal electrodes to a multilayered ceramic capacitor with minimized structural defects such as cracks or delamination. The palladium powder is produced by spraying a palladium salt solution containing one or more alkaline earth metal elements to form droplets and heating the droplets to a temperature of at least 1000.degree. C. The preferred amount of the alkaline earth metal elements in the Pd powder is from 0.005 to 0.1% by weight relative to Pd and the preferred alkaline earth metal elements are one or more elements selected from the group consisting of Mg, Ca, Sr and Ba.

Growing community of inventors

Fukuoka, Japan

Masayuki Maekawa