Preparation of niobium nanoparticles by sodiothermic reduction of Nb2O5 in molten salts

Niobium nanoparticles with high purity were prepared by a sodiothermic reduction process using Nb2O5 as the raw material, LiCl, NaCl, KCl and CaCl2 as the diluents and sodium as the reducing reagent. The effects of the different molten salt systems, CaCl2 content, reaction time, excessive sodium and reaction temperature on the characteristics of the obtained niobium powder were discussed. The as-prepared niobium nanoparticles under the optimum experimental conditions were obtained by sodiothermic reduction with 20% excessive sodium in the NaCl-52mol%CaCl2-2mol%Nb2O5 molten salts at 650 °C for 6 h, and the molar ratio of the oxygen element in Nb2O5 and the CaCl2 of the molten salts is less than 19.23% at 750 °C. Moreover, the particle size of niobium nanoparticles is ranged about 40∼240 nm with increasing of reaction temperature from 650 to 800 °C.