Shoei Chemical Inc.

Sec Corporation

Fumiyuki Shimizu

Yuji Akimoto

Masayuki Maekawa

Kazuro Nagashima

Eiichi Asada

Naoto Shindo

Mineto Iwasaki

Tomotaka Nishikawa

Shusaku Kawaguchi

Kenji Morinaga

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

A metal powder having a vitreous thin layer on at least a part of the surface thereof wherein the amount of the vitreous thin layer is preferably 0.01 to 50% by weight based on the metal powder without the vitreous thin layer. The metal powder is prepared by a process comprising the steps of: bringing a solution comprising a heat-decomposable metal compound to fine droplets; and heating the droplets to a temperature above the decomposition temperature of the metal compound, wherein a precursor of an oxide, heat-decomposable to produce a vitreous material which, together with the metal, does not form a solid solution, is added to the solution and the vitreous material is deposited, upon the heating, in the vicinity of the surface of the metal powder. The powder is useful for the preparation of a thick film paste used in a multilayer ceramic electronic component or substrate, since it has an excellent oxidation resistance during storage, in a conductor paste, and during firing of the paste.

Metal powder and process for preparing the same

A crystallized glass for a substrate of an information-recording disk, which has been obtained by melting a glass forming material consisting essentially of, in wt. % as oxide, 55 to 85% of SiO.sub.2, 5 to 20% of Li.sub.2 O, 0 to 10% of K.sub.2 O+Na.sub.2 O, 0 to 10% of MgO, 0 to 20% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 10% of ZnO, 0 to 10% of Al.sub.2 O.sub.3, 0 to 15% of B.sub.2 O.sub.3, 0 to 6% of P.sub.2 O.sub.5, 0 to 3% of TiO.sub.2, 0 to 3% of ZrO.sub.2, 0 to 3% of SnO.sub.2 and 0 to 1% of As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3, 0.1 to 10 wt. % of F and 0.1 to 20 wt. % of Cl, molding, vitrifying and crystallizing the material, and which contains at least 0.05% by weight of chlorine after crystallization. The glass forming material may further contain 0 to 10% of Fe.sub.2 O.sub.3, 0 to 10% of Cr.sub.2 O.sub.3, 0 to 10% of NiO, 0 to 10% of V.sub.2 O.sub.5, 0 to 10% of CuO, 0 to 10% of MnO.sub.2, 0 to 10% of MoO.sub.3, the total of Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3 +NiO+V.sub.2 O.sub.5 +CuO+MnO.sub.2 +MoO.sub.3 being 0.5 to 10%, and 0 to 3% of CeO.sub.2. The crystallized glass has a microcrystalline structure and surface properties desirable as a substrate material for an information-recording disk as well as excellent meltability and moldability.

Crystallized glass for substrate of information-recording disk

Growing community of inventors

Chikushino, Japan

Fumiyuki Shimizu