The Effect of Different Molten Salt Composition on Morphology and Purity of the ZrB2 Powder Obtained via Direct Molten Salt Reaction Method

Zirconium Diboride (ZrB2) powder was synthesized at low temperature via a Direct Molten Salt Reaction (DMSR) method. The influence of different salt compositions including the eutectic mixture of (KF-NaF), (KF-KCl) and (KCl-NaCl) on the morphology and purity of the reaction products was studied. The obtained samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Furthermore, the formation mechanism of ZrB2 was investigated by DTA/TG. The results show that alongside eutectic mixture of chloride salt, the ZrB2 powder can be obtained by eutectic mixture of the fluoride salt. In addition, the obtained ZrB2 powder without additional salt has hexagonal prism morphology, whereas the ZrB2 particles prepared by the eutectic mixture of fluoride salt have higher purity and particle size and hexagonal morphology as well. The synthesized ZrB2 powder in chlorofluoride salt has lower particle size and purity and non-uniform morphology. The synthesized ZrB2 powder is different from the starting material in term of morphology and particle size. Therefore, the dissolution–precipitation mechanism may play a dominant role in the synthesis of ZrB2 during the DMSR process.