I. V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Scientific Centre, Russian Academy of Sciences

V. M. Orlov, Head of Laboratory, e-mail: orlov@chemy.kolasc.net.ru
V. N. Kolosov, Leading Researcher
T. Yu. Prokhorov, Senior Researcher
M. N. Miroshnichenko, Junior Researcher

The processing of electron beam melted and sodiumthermal tantalum capacitor grade powders has been investigated. The technology of electron beam melted agglomerated capacitor grade powders with a charge of 5000–7000 μC/g is described. Its characteristic features are the combination of dehydration and sintering processes, as well as the utilization of hydrogen liberated in the dehydrogenation process with its subsequent use for the hydride. Performed comprehensive studies of the process of sodium-thermal tantalum powders has been investigated showed that the most promising method of obtaining them is to restore from a melt containing potassium heptafluorotantalate (liquid-phase reduction). At the same time methods for diminishing the contents of apparatus impurities in powders and enlarging their surface have been developed. It has been shown that oxygen, added to a tantalate-containing melt at the initial stage of reduction process, promotes the growth of powder particles, including after the addition of new fluorotantalate batches to the melt. The resulting sodiumthermal capacitor powders had a specific charge of 10 000 to 70 000 μC/g.

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