Abstract: A Ta—Nb alloy powder which provides a capacitor having a higher capacitance than a Ta capacitor and a better thermal stability in terms of an oxide film than a Nb capacitor, the Ta—Nb alloy powder being a Ta—Nb alloy powder produced by a thermal CVD method, wherein a content of Nb is 1 to 50 mass %, and an average particle diameter of primary particles is 30 to 200 nm, preferably, a CV value per unit mass of the powder (?F·V/g) is 250 k?F·V/g or more, or further, a CV value per unit volume (?F·V/mm3) in terms of a molded body whose molding density ? (g/cm3) is ?c (g/cm3)=?0.012RNb+3.57, wherein RNb:Nb content (mass %) in an alloy, is 900 ?F·V/mm3 or more, and an anode element for a solid electrolytic capacitor using the alloy powder.

Abstract: A Ta-Nb alloy powder which has provides a capacitor having a higher capacitance than a Ta capacitor and a better thermal stability in terms of an oxide film is better than a Nb capacitor, the Ta-Nb alloy powder being a Ta-Nb alloy powder produced by a thermal CVD method, wherein a content of Nb is 1 to 50 mass %, and an average particle diameter of primary particles is 30 to 200 nm, preferably, a CV value per unit mass of the powder (?F·V/g) is 250 k?F·V/g or more, or further, a CV value per unit volume (?F·V/mm3) in terms of a molded body whose molding density ? (g/cm3) is ?c (g/cm3)=?0.012RNb+3.57, wherein RNb: Nb content (mass %) in an alloy, is 900 ?F·V/mm3 or more, and an anode element for a solid electrolytic capacitor using the alloy powder.

Abstract: Method of producing Ta powder for tantalum solid electrolytic capacitor capable of stably providing CV value of more than 220 k and to provide the Ta powder and its Ta granulated powder. In method of producing Ta powder by vaporizing TaCl5 through heating and reducing with H2 gas, the reduction is performed under conditions that feeding rate of TaCl5 vapor passing through section area of reaction field of 1 cm2 for 1 minute is 0.05˜5.0 g/cm2·min and residence time of TaCl5 vapor in the reduction reaction field is 0.1˜5 seconds and reduction temperature of TaCl5 is 1100˜1600° C., whereby Ta powder including a single phase of ?-Ta of tetragonal system or mixed phase of ?-Ta and ?-Ta of cubic system and having average particle size of 30˜150 nm is obtained. Further, Ta granulated powder is obtained by granulating the Ta powder.