Influence of the precursor composition and the reduction conditions on the characteristics of magnesium-thermic niobium powders

The influence of the composition and the conditions of the reduction of niobium oxide compounds with magnesium vapor on the specific surface area of the produced metallic powder is studied. When magnesium niobate Mg 4 Nb 2 O 9 is used as a precursor, the specific surface of the powder increases by several times compared to that of an Nb 2 O 5 precursor. Niobium powders with the specific surface up to 150 m 2 g –1 (calculated particle size 4.7 nm) and a bulk density of 0.8 g cm –3 are formed by the reduction of Mg 4 Nb 2 O 9 . The powders are characterized by a mesoporous structure, and the most part of the specific surface consists of pores with a diameter less than 4 nm.