Abstract
Nb–Al intermetallic powders were synthesized via sodiothermic reduction process in NaCl–CaCl2 molten salts using Nb2O5 and Al2O3 as raw materials. The as-prepared samples were characterized by X-ray diffraction and scanning electron microscopy. The homogeneity of Nb2O5/Al2O3 composites was investigated by mechanical ball-milling process using Nb2O5 and Al2O3 with heavy aggregation at the different times. It was found that the homogeneous Nb2O5/Al2O3 composites were obtained after ball-milling for 10h. Using these homogeneous Nb2O5/Al2O3 composites with a molar ratio of 4:1, 1:3 and 1:1 as precursors, Nb–Al intermetallic powders of Nb3Al, NbAl3 and the mixture of Nb2Al and NbAl3 were produced in NaCl–CaCl2 molten salts at 700°C. In comparison, the Nb2Al/NbAl3 composites were also fabricated using single-phase Na2NbAlO5 synthesized using Nb2O5 and NaAlO2 as raw materials in molten NaCl–KCl, which is ascribed to the homogenous distribution of Nb and Al in the multi-phase oxides.
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