Preparation of niobium aluminides intermetallic powders by sodiothermic reduction process

The niobium aluminides intermetallic particles were prepared by a sodiothermic reduction process using Nb₂O₅ and NaAlO₂ as raw materials, NaCl and CaCl₂ as the diluents and sodium as a reducing agent. The phases, morphology and particle size of niobium aluminides intermetallic powders depending on the molar ratio of oxygen in raw materials and CaCl₂ in the molten salt, the atomic ratio of niobium and aluminum in raw materials and premelting time in molten salts were analyzed. The NbAl₃ and Nb₃Al particles are obtained at 680°C and 750°C for the 6.0 h premelting time, respectively, and the particle size of NbAl₃ and Nb₃Al powders is about 50~260 nm and 30~180 nm. Besides, the purity of the niobium aluminides intermetallics powders was increased along with the increasing of the premelting time.