Abstract: Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Abstract: Provided is a tungsten electrode material that can improve the life of an electrode than conventional by the use of a material in place of thorium oxide. The tungsten electrode material includes a tungsten base alloy and oxide particles dispersed in the tungsten base alloy, wherein the oxide particle is an oxide solid solution in which a Zr oxide and/or a Hf oxide and an oxide of at least one or more kinds of rare earth elements selected from Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu are solid-dissolved.

Abstract: A composite member has a substrate made of a composite material having SiC combined with magnesium or a magnesium alloy, and has a warpage degree of not less than 0.01×10?3 and not more than 10×10?3, the warpage degree being defined as lmax/Dmax, where lmax being a difference between a maximum value and a minimum value of surface displacement of one surface of composite member measured along a longest side thereof, and Dmax being a length of the longest side. Thereby, a composite member capable of efficiently dissipating heat to an installation object, a heat-dissipating member using the composite member, and a semiconductor device having the heat-dissipating member are provided.

Abstract: Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Abstract: A method of producing sodium tungstate of this invention including allowing cemented carbide scrap containing tungsten to react with a molten salt containing sodium sulfate and having added thereto a metal oxide, to thereby obtain sodium tungstate.

Abstract: There is provided a metal laminated structure comprising a first metal layer, a second metal layer and a third metal layer, the first metal layer being disposed on one surface of the second metal layer, the third metal layer being disposed on the other surface of the second metal layer, the first metal layer including at least one of tungsten and molybdenum, the second metal layer including copper, the third metal layer including at least one of tungsten and molybdenum, and a method for producing the metal laminated structure.

Abstract: An object of this invention is to provide a crucible for growing a sapphire single crystal, which is optimized for providing a sapphire single crystal and is reusable. A crucible for growing a sapphire single crystal of this invention includes: a base material (3) containing molybdenum as a main component and having a crucible shape; and a coating layer (5) with which only an inner periphery of the base material (3) is coated and which is formed of tungsten and inevitable impurities, in which the coating layer (5) has a surface roughness Ra of 5 ?m or more and 20 ?m or less.

Abstract: One object of the present invention is to provide a wire drawing die excellent in strength and wear resistance. The wire drawing die has a core formed using highly hard diamond polycrystalline body made substantially only of diamond and produced by directly converting a raw material composition including a non-diamond type carbon material into diamond and sintering the diamond at an ultra high pressure and an ultra high temperature without adding a sintering aid or a catalyst, the polycrystalline body having a mixed construction including fine-grained diamond crystals with a maximum grain size of less than or equal to 100 nm and an average grain size of less than or equal to 50 nm and plate-like or particulate coarse-grained diamond crystals with a minimum grain size of greater than or equal to 50 nm and a maximum grain size of less than or equal to 10000 nm.

Abstract: A composite member suitable for a heat radiation member of a semiconductor element and a method of manufacturing the same are provided. This composite member is a composite of magnesium or a magnesium alloy and SiC, and it has porosity lower than 3%. This composite member can be manufactured by forming an oxide film on a surface of raw material SiC, arranging coated SiC having the oxide film formed in a cast, and infiltrating this coated SiC aggregate with a molten metal (magnesium or the magnesium alloy). The porosity of the composite member can be lowered by improving wettability between SiC and the molten metal by forming the oxide film. According to this manufacturing method, a composite member having excellent thermal characteristics such as a coefficient of thermal expansion not lower than 4 ppm/K and not higher than 10 ppm/K and thermal conductivity not lower than 180 W/m·K can be manufactured.

Abstract: The super abrasive wheel includes a core rotating around a rotation axis and a super abrasive layer bonded to the core. The core has a first surface and a second surface located opposite to the first surface. An annular first protrusion portion protruding in the direction away from the first surface is provided at a portion of the second surface that is surrounded with the super abrasive layer. A reference surface is provided in the second surface on the inside of the first protrusion portion. The height from the reference surface to the first protrusion portion is denoted as A. A top portion having the height B from the reference surface is provided at a portion of the second surface between the first protrusion portion and the super abrasive layer. The height B is greater than the height A.

Abstract: There is provided a metal laminated structure in which a first metal layer containing tungsten is provided on a first surface of a second metal layer containing copper and a third metal layer containing tungsten is provided on a second surface of the second metal layer opposite to the first surface, and the first metal layer contains crystal grains of tungsten in a form of a columnar crystal extending in a direction perpendicular to the first surface of the second metal layer and the third metal layer contains crystal grains of tungsten in a form of a columnar crystal extending in a direction perpendicular to the second surface of the second metal layer, and a method for producing the metal laminated structure.

Abstract: A method for producing an ammonium tungstate aqueous solution includes the steps of: adding sulfuric acid to a solution containing tungstate ions; bringing the solution having the sulfuric acid added therein, into contact with an anion exchange resin; and bringing the anion exchange resin into contact with an aqueous solution containing ammonium ions.

Abstract: Provided is a Mo—Si—B-based alloy for a heat-resistant alloy that satisfies, more than conventional, physical properties such as proof stress and hardness adapted to an increase in the melting point of a welding object. A Mo—Si—B-based alloy powder of this invention is such that the full width at half maximum of (600) of Mo5SiB2 in X-ray diffraction peak data is 0.08 degrees or more and 0.7 degrees or less.

Abstract: Provided is a heat-resistant alloy that satisfies physical properties such as proof stress and hardness adapted to an increase in the melting point of a welding object compared to conventional alloys. A heat-resistant alloy of this invention includes a first phase, as a main component, containing a Mo or W metal phase, a second phase containing a Mo—Si—B-based alloy, and a third phase containing titanium carbonitride, wherein the balance is inevitable compounds and inevitable impurities.

Abstract: There is provided a flat plate-like sintered tungsten alloy that can be molded into a complex shape by press working or forge processing. The flat plate-like sintered tungsten alloy contains 85% by mass or more and 98% by mass or less of W, 1.4% by mass or more and 11% by mass or less of Ni, and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of Fe, Cu and Co, wherein an elongation percentage of the flat plate-like sintered tungsten alloy in a planar direction is 20% or more.

Abstract: There are provided a cemented carbide high in thermal diffusivity and excellent in wear resistance, and a cutting tool including a base material formed of this cemented carbide. The cemented carbide is a WC based cemented carbide in which a hard phase mainly constituted of WC grains is bound by a binder phase mainly constituted of Co, and is used for a cutting tool. The binder phase is substantially constituted of Co, or Co and Ni. A total content of Co and Ni is not less than 4.5 mass % and not more than 15 mass %. In this cemented carbide, the WC grains have an average diameter of not less than 0.4 ?m and not more than 4 ?m.

Abstract: Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Abstract: Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Abstract: An electrodeposited wire tool has a core wire extending in a longitudinal direction, a plating layer provided on an outer peripheral surface of the core wire, superabrasive grains held by the plating layer and coating layers covering the outer peripheral surfaces of the superabrasive grains. The coating layers are constituted of electroless Ni—P platings. The coating layers are heat-treated, and the electroless Ni—P platings are partially or entirely crystallized.