Heat Treatment of Tantalum and Niobium Powders Prepared by Magnesium-Thermic Reduction

Changes in the specific surface area and porous structure of tantalum and niobium powders, which were prepared by magnesium-thermic reduction of Ta 2 O 5 , Mg 4 Ta 2 O 9 , and Mg 4 Nb 2 O 9 oxide compounds and subjected to heat treatments at temperatures of 600–1500°C, have been studied. It is noted that, owing to the mesoporous structure of the magnesium-thermic powders, the decrease in the surface area during heat treatment, first of all, is related to a decrease in the amount of pores less than 10 nm in size. The heat treatment of a reacting mass is shown to allow us to correct the specific surface area of the powder without any increase in the oxygen content in it. Data on the effect of heat treatment conditions on the specific charge of capacitor anodes are reported.