Characteristic Variation of Niobium Powder Produced under Various Reduction Temperature and Amount of Reductant Addition

Niobium powder was fabricated by sodiothermic reduction process using K2NbF7 as the raw materials, KCl and KF as the diluents and Na as the reducing agent. The apparatus for the experiment was designed and built specifically for the present study. Varying properties of niobium powder depending on reaction temperature and excess of reducing agent were analyzed. The niobium particle size increased significantly as the reduction temperature increased from 993 to 1093 K. The particle size was fairly uniform at a given reaction temperature, varying from 0.2 mu m to 50 nm, depending on the reaction temperature. The yield of niobium powder increased from 58 to 83% with a increasing a reaction temperature. The average particle size of niobium powder is improved from 70 nm to 0.2 gm with a increasing amount of sodium excess. And the yield ratio of Nb powder was 82% in the 5% excess sodium. [doi:10.2320/matertrans.M2009192]