Abstract: A tungsten recovery method including leaching tungsten while suppressing leaching of silicon by using a weak alkali compound with respect to a tungsten raw material containing silicon with tungsten oxide, separating most of the silicon as a residue during the leaching of the tungsten, and recovering a tungsten leachate having an extremely low silicon concentration.

Abstract: Provided is a super-hard sintered material which contains 5 to 55 mass % of W and a WC balance containing inevitable impurities and is excellent in high hardness and high strength.

Abstract: Provided is a method for producing a high-purity tungsten powder having a phosphorus content of less than 1 wtppm; wherein an ammonium tungstate solution containing 1 wtppm or more of phosphorus as an impurity in terms of the inclusion in tungsten is used as a starting material, this solution is neutralized with hydrochloric acid at a temperature of 50° C. or less to adjust the pH at 4 or more and less than 7 so as to precipitate ammonium paratungstate undecahydrate crystals, the resulting solution is heated to 70 to 90° C. and filtered in a high-temperature state so as to obtain ammonium paratungstate pentahydrate crystals, the obtained crystals are calcined so as to form a tungsten oxide, and the tungsten oxide is subject to hydrogen reduction so as to obtain a high-purity tungsten powder. Additionally provided is a method for producing a high-purity tungsten powder having a phosphorus content of 0.

Abstract: Disclosed is a wear-resistant particle which can be substantially uniformly dispersed in a molten pool. Specifically disclosed is a wear-resistant particle (13) which is dispersed in a matrix metal for improving wear resistance thereof. The wear-resistant particle is characterized by being composed of a material containing a first hard material and a second hard material while having a particle diameter of 0.2-9 mm. The wear-resistant particle is further characterized in that the material consists of 60-96% by volume of a carbide and the balance of a metal.

Abstract: Provided is a method for producing a high-purity tungsten powder having a phosphorus content of less than 1 wtppm; wherein an ammonium tungstate solution containing 1 wtppm or more of phosphorus as an impurity in terms of the inclusion in tungsten is used as a starting material, this solution is neutralized with hydrochloric acid at a temperature of 50° C. or less to adjust the pH at 4 or more and less than 7 so as to precipitate ammonium paratungstate undecahydrate crystals, the resulting solution is heated to 70 to 90° C. and filtered in a high-temperature state so as to obtain ammonium paratungstate pentahydrate crystals, the obtained crystals are calcined so as to form a tungsten oxide, and the tungsten oxide is subject to hydrogen reduction so as to obtain a high-purity tungsten powder. Additionally provided is a method for producing a high-purity tungsten powder having a phosphorus content of 0.

Abstract: In a nonaqueous electrolyte secondary battery and an active material for a nonaqueous electrolyte secondary battery, the nonaqueous electrolyte secondary battery includes: a positive electrode containing a positive-electrode active material; a negative electrode containing a negative-electrode active material; and a nonaqueous electrolyte, wherein molybdenum dioxide whose particles have an average aspect ratio of two or less is used as the positive-electrode active material or the negative-electrode active material where the aspect ratio is the ratio between the major axis length and the minor axis length of a particle-equivalent ellipse equivalent to the cross-sectional area or the two-dimensional projection image of each of the observed particles (major axis length/minor axis length), the particle-equivalent ellipse being an ellipse having the same area and the same first and second moments as the observed particle.

Abstract: A sintered sputtering target for forming a high purity metal Mo thin film having a remarkably little particle generation is provided. A high purity metal Mo coarse powder as a raw material is provided for making this target. The sintered sputtering target has a theoretical density ratio of 98% or more. The target is obtained by sintering the high purity metal Mo coarse powder. This particle powder has the high purity of 99.99 or more % by mass and an average particle diameter of 5.5 to 7.5 ?m.

Abstract: A process is provided for producing a fine tungsten carbide powder, which comprises the steps of drying a slurry, which is obtained by mixing an aqueous ammonium tungstate solution with a carbon powder, at low temperature, to form a precursor, mixing a reduction and carburization product, which is obtained by reducing and oxidizing the precursor in an inert gas, with a carbon powder in a proportion required to substantially carburize the entire tungsten component into tungsten carbide (WC), and carburizing the mixture; and a high-performance fine tungsten carbide powder produced by the process, which has an average particle size of 0.8 ?m or less and is free of a coarse power having a particle size of more than 1 ?m, and which also contains less metal impurities and contains oxygen and nitrogen in a predetermined amount.

Abstract: A sintered sputtering target for forming a high purity metal Mo thin film having a remarkably little particle generation is provided. A high purity metal Mo coarse powder as a raw material is provided for making this target. The sintered sputtering target has a theoretical density ratio of 98% or more. The target is obtained by sintering the high purity metal Mo coarse powder. This particle powder has the high purity of 99.99 or more % by mass and an average particle diameter of 5.5 to 7.5 ?m.

Abstract: A process is provided for producing a fine tungsten carbide powder, which comprises the steps of drying a slurry, which is obtained by mixing an aqueous ammonium tungstate solution with a carbon powder, at low temperature, to form a precursor, mixing a reduction and carburization product, which is obtained by reducing and oxidizing the precursor in an inert gas, with a carbon powder in a proportion required to substantially carburize the entire tungsten component into tungsten carbide (WC), and carburizing the mixture; and a high-performance fine tungsten carbide powder produced by the process, which has an average particle size of 0.8 ?m or less and is free of a coarse power having a particle size of more than 1 ?m, and which also contains less metal impurities and contains oxygen and nitrogen in a predetermined amount.