Room-Temperature Mechanochemical Synthesis of W2B5 Powders

The mechanochemical synthesis of W₂B₅ powders was successfully carried out at room temperature. WO_2.72, B₂O₃ and Mg powder blends were mixed to form batches according to the metallothermic reduction of WO_2.72 and B₂O₃ with Mg, which were subsequently mechanically alloyed (MA) using a Spex mill at different durations to constitute W₂B₅ + MgO as final products. Following mechanochemical synthesis, MgO was removed from the system by leaching the powders with HCl. Microstructural and morphological characterizations of boride powders were carried out via scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. Moreover, atomic absorption spectroscopy (AAS) and differential scanning calorimetry (DSC) experiments were carried out to monitor the purity of the powders at different stages of the process. After mechanical alloying of the powder batches comprising 50 pct stoichiometrically excess amount of B₂O₃ for 30 hours and leaching with a 7 M HCl solution, pure W₂B₅ powders with an average particle size of 226 nm and an average grain size of 55.3 nm were successfully synthesized.