Preparation of single phase molybdenum boride

The formation of MoB through volume combustion synthesis (VCS), and through mechanochemical synthesis (MCS) followed by annealing has been investigated. MoO3, B2O3 and Mg were used as reactants while MgO and NaCl were introduced as diluents. Products were leached in dilute HCl solution and were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examinations. Mo was the major phase component in the VCS products under all the experimental conditions. Mo2B, MoB, MoB2 and Mo2B5 were found as minor phases. Products of MCS contained a mixture of Mo2B, MoB, MoB2 and Mo. After annealing the MCS product at 1400 °C for 3 h, single phase α-MoB was obtained.

► Formation of Mo and a mixture of molybdenum boride phases take place in preparation of molybdenum borides.
► It is intricate to prepare single phase molybdenum borides.
► Formation of single phase MoB from MoO3 + B2O3 + Mg mixtures has not been reported previously.
► Single phase MoB was successfully prepared through a combination of mechanochemical synthesis and annealing process.