Nippon Steel Corporation

Electro Plasma, Inc.

Koichi Takeda

Akihiro Miyasaka

Erich Muehlberger

Hiroyuki Ogawa

Jiro Kondo

Tetsuo Ishitsuka

Goro Saiki

Albert Sickinger

Satoshi Araki

Kozo Denpo

Tsuyoshi Shinoda

Masamichi Koga

Don E Bailey

Stephan E Meuhlberger

Tutomu Ooki

Mutsuo Maki

A supersonic plasma system in which a vacuum source creates a low static pressure environment within an enclosure containing a plasma gun and a workpiece has plural cathodes of sealed, modular construction in conjunction with a common anode, to provide higher levels of operating power and other advantages which flow from a segmented cathode gun configuration. Inert gas independently introduced into the plural cathodes undergoes swirling motion over the cathode tips. The anode is of modular construction for easy replacement in order to change the configuration of a nozzle, a plurality of arc chambers receiving the plural cathodes or a central mixing chamber between the nozzle and the arc chambers within the anode and coupled to a central powder feed. The powder feed includes a replaceable insert which includes at least one and preferably a plurality of powder feed ports into the various arc chambers. Alternatively, metal which has already been heated to a molten state can be fed directly into the central mixing chamber. The modular cathodes which are independently powered by separate D.C. power sources are also independently cooled by separate cooling water systems as is the common anode. The cooling systems are configured to produce swirling of the cooling water so that cooling action is maximized.

Modular segmented cathode plasma generator

An alloy exhibiting corrosion resistance in a combustion environment where V, Na, S and Cl are present comprises, in weight percent, not more than 0.05% C, 0.02-0.5% Si, 0.02-0.5% Mn, 15-35% Cr, 0.5-4% Mo, more than 40% but not more than 60% Co, 5-15% Fe, 0.5-5% W, 0.0003-0.005% Ca and the remainder of Ni at a content of not less than 4% and unavoidable impurities, provided that Cr (%)+0.5Ni (%)+3Mo (%).gtoreq.30 (%). A composite steel tube exhibiting corrosion resistance in a combustion environment where V, Na, S and Cl are present comprises an inner tube constituted of Cr-containing boiler tube and an outer tube constituted of the alloy.

Alloy and composite steel tube with corrosion resistance in combustion

Ultrafine particles of metals, metallic compounds, and ceramics can be produced by heating a starting material supplied hermetically with a plurality of direct current plasma currents combined at a central axis of a work coil for generating high frequency induction plasma positioned under the direct current plasma generated zone. Apparatuses used therefor are also disclosed.

Process for producing ultrafine particles of metals, metal compounds and

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Kawasaki, Japan

Koichi Takeda