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

Resumo

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 Mg₄Nb₂O₉ is used as a precursor, the specific surface of the powder increases by several times compared to that of an Nb₂O₅ precursor. Niobium powders with the specific surface up to 150 m² g^–1 (calculated particle size 4.7 nm) and a bulk density of 0.8 g cm^–3 are formed by the reduction of Mg₄Nb₂O₉. 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.