A new route for the synthesis of NdB6 powder from Nd2O3–B4C system

The neodymium hexaboride NdB6 powder has been synthesized by the reduction of Nd2O3 with B4C from Nd2O3–B4C system under the conditions of high temperature and high vacuum. Thermodynamic and dynamic analyses show that synthetic temperature and partial pressure in the furnace are the most important determinants during the synthesis. According to the results of thermodynamic calculation and differential scanning calorimetry (DSC), the synthetic process was determined. The compositions of products achieved at different temperatures and different holding times were identified by X-ray diffraction (XRD). The characters of powder were observed by scanning electronic microscope (SEM). It is concluded that after a series of pretreatments, NdB6 powders are fabricated from Nd2O3–B4C system under the conditions of 10−2 Pa vacuum and 4 h holding time with synthetic temperature above 1773 K. The diameter of NdB6 ranges from 2 to 4 μm.