A novel and simple method for large-scale synthesis of nanosized NbC powder by disproportionation reaction in molten salt

摘要

Nanosized niobium carbide (NbC) powder was successfully synthesized by disproportionation reaction of Nb(IV) species in NaCl-KCl molten salt at 800-900 degrees C for 0.5-5 h by using a mixture of Nb, NbCl5, and acetylene black as raw materials. Effects of molar ratio of NbCl5/Nb, temperature, and reaction time on NbC preparation were also investigated. The composition and microstructure of the product were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). Homogenous NbC powder with a particle size of similar to 50 nm is in-situ synthesized on template of acetylene black by disproportionation reaction of Nb(IV) species in NaCl-KCl molten salt. In addition, NbC formation is dramatically influenced by molar ratio of NbCl5/Nb and temperature, a higher temperature and higher molar ratio of NbCl5/Nb are more preferable for nanosized NbC powder formation.