Jfe Mineral Company, Ltd.

Kawasaki Steel Corporation

Kawatetsu Mining Co., Ltd.

Tadasu Kirihara

Nobuyuki Sato

Osamu Ebato

Kan Saito

Tetsuya Fujii

Yoshiei Kato

Seiji Taguchi

Masahito Suito

Shigeru Omiya

In a hydrogen-containing tantalum powder of the present invention, a value obtained by dividing the hydrogen content (ppm) by the specific surface area (m/g) is in the range of 10 to 100. This tantalum powder has a large specific surface area, and when the tantalum powder is used as an anode of a solid electrolyte capacitor, a solid electrolyte capacitor having a large capacitance and a low leakage current can be obtained.

Tantalum powder and solid electrolyte capacitor including the same

There is provided a niobium alloy powder suitable for manufacturing solid electrolytic capacitors having small leakage currents and high capacitances, where the powder is obtained by enhancing the thermal stability of the niobium oxide coating film while improving the temperature dependence of the sintering behavior of the powder. The niobium alloy powder includes one or more of molybdenum, chromium, and tungsten each with a content of 0.002 to 20% by mass, and phosphorus and boron each with a content of 0.002 to 5% by mass, and moreover, includes hydrogen with a content of 0.005 to 0.10% by mass, the balance being substantially niobium; the specific surface area of the powder is from 1 to 20 m/g; the powder has a cumulative pore volume of 0.2 ml/g or more; and the cumulative volume of the pores each having a diameter of 1 &#x3bc;m or less makes up 10% or more and the cumulative volume of the pores each having a diameter of 10 &#x3bc;m or less makes up 40% or more in relation to the total cumulative pore volume.

Niobium alloy powder, anode for solid electrolytic capacitor and solid electrolytic capacitor

A niobium powder is provided for producing a niobium capacitor enhanced in the thermal stability of oxide films on niobium, with less leak current and less deterioration of leak current after application of thermal loads. The niobium powder contains form 0.005 to 0.10 mass % of hydrogen and from 0.002 to 5 mass % of sulfur and, further preferably, one or both of magnesium and aluminum in an amount from 0.002 to 1 mass % in total. The specific surface area of the powder is 1 to 10 m /g and the average particle diameter of the secondary particles is 10 to 200 &mgr;m.

Niobium powder and solid electrolytic capacitor using the same

Disclosed is a method of refining of a high purity steel capable of effectively lowering impurities in molten steel into respective ultra-low ranges. In secondary refining for molten steel after a molten iron prerefining process and a converting process, a reducing agent and a flux are added on the bath surface within a ladle containing the molten steel decarburized in a converter so that the composition of slag on the bath surface is adjusted in such a manner that the total concentration of FeO and MnO becomes 5 wt % or less, and subsequently, impurities in the molten steel are effectively lowered into respective ultra-low ranges using a RH vacuum degassing unit.

Method of refining of high purity steel

Growing community of inventors

Chiba, Japan

Tadasu Kirihara