Molten salt synthesis, characterization, and formation mechanism of superfine (HfxZr1-x)B2 solid-solution powders

Abstract

High-purity superfine (Hf x Zr 1-x )B 2 solid-solution powders with various chemical compositions (x = 0.2, 0.5, and 0.8) were successfully synthesized via molten salt synthesis technique at 1423 K using ZrO 2 , HfO 2 , and 20% excessive B as precursors within a KCl/NaCl molten salt for the first time. The results showed that the as-synthesized solid-solution powders exhibited the irregular polyhedral morphology with the average particle sizes of 170–185 nm and simultaneously possessed a single-crystalline hexagonal structure and good compositional uniformity from nanoscale to microscale. In addition, their formation mechanisms were well interpreted by analyzing the thermodynamics of the possible chemical reactions in the molten salt.