Cabot Supermetals K.k.

Yukio Oda

Tomoo Izumi

Yoshikazu Noguchi

Yujiro Mizusaki

Isayuki Horio

An object of the present invention is to provide nitrogen-containing metallic powder at high productivity, which powder contains a metal such as niobium or tantalum containing nitrogen uniformly, and enables production of an anode electrode that has high specific capacitance and low leakage current and that exhibits excellent reliability for a prolonged period of time. There is provided nitrogen-containing metallic powder which is a solid solution containing 50-20,000 ppm nitrogen, in which the metal that constitutes the metallic powder is niobium or tantalum. The nitrogen-containing metallic powder is produced through the process in which while a metallic compound is reduced with a reducing agent, a nitrogen-containing gas is introduced into a reaction system to thereby form metal, and nitrogen is simultaneously incorporated into metal. A porous sintered body comprising the nitrogen-containing metallic powder and a solid electrolytic capacitor comprising the powder have low leakage current and exhibit excellent reliability for a prolonged period of time.

Nitrogen-containing metal powder, production process thereof, and porous sintered body and solid electrolytic capacitor using the metal powder

A niobium or tantalum powder of the present invention comprises aggregates in which primary particles of niobium or tantalum are aggregated, and have a pore distribution having a peak in the range from 1 to 20 &#x3bc;m as measured by mercury porosimetry. That is, the niobium or tantalum powder of the present invention comprises aggregates having large pores, which connect with vacancies between the primary particles and facilitate the permeation of an electrolyte over the entirety of the inside of each aggregate. Accordingly, a solid electrolytic capacitor comprising an anode electrode made of the niobium or tantalum powder has high capacity and also a low ESR.

Niobium or tantalum powder and method for production thereof, and solid electrolytic capacitor

An object of the present invention is to provide nitrogen-containing metallic powder at high productivity, which powder contains a metal such as niobium or tantalum containing nitrogen uniformly, and enables production of an anode electrode that has high specific capacitance and low leakage current and that exhibits excellent reliability for a prolonged period of time. There is provided nitrogen-containing metallic powder which is a solid solution containing 50&#x2013;20,000 ppm nitrogen, in which the metal that constitutes the metallic powder is niobium or tantalum. The nitrogen-containing metallic powder is produced through the process in which while a metallic compound is reduced with a reducing agent, a nitrogen-containing gas is introduced into a reaction system to thereby form metal, and nitrogen is simultaneously incorporated into metal. A porous sintered body comprising the nitrogen-containing metallic powder and a solid electrolytic capacitor comprising the powder have low leakage current and exhibit excellent reliability for a prolonged period of time.

A nitrogen containing metal powder wicth a large specific surface area, and containing a suitable quantity of nitrogen dispersed uniformly within the metal is produced with good productivity, and provides a solid electrolytic capacitor with a high capacitance, minimal leakage current, and excellent long term reliability. This nitrogen containing metal powder has a ratio W/S between the nitrogen content W [ppm] of the powder, and the specific surface area S [m/g], as measured by a BET method, that falls within a range from 500 to 3000. This type of powder can be produced by a process in which a metal salt containing the metal is reacted with a reducing agent and undergoes reduction within a diluent salt, thereby generating the metal, wherein a nitrogen containing gas is introduced into the space contacting the reaction melt comprising the metal salt, the reducing agent and the diluent salt, thereby generating the metal and incorporating the nitrogen within the metal.

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Fukushima, Japan

Yukio Oda