Abstract:

The present study reports the in-situ synthesis of hybrid powders containing vanadium borides (VB2, V3B4 and V2B3) and vanadium carbide (VC) using powder metallurgy methods. VB2-V3B4-V2B3/VC hybrid powders were synthesized from V2O5, B2O3 and C powder blends via a carbothermal reduction route assisted by mechanical milling. Powder blends were mechanically milled up to 5 h in a high-energy ball mill. The milling process reduced the crystallite size, increased the uniformity of the particle distribution and hence increased the reactivity of the starting powders. As-blended and milled powders were annealed at different temperatures (1400, 1500 and 1600°C) for 12 h to investigate the probability of achieving vanadium boride and carbide phases simultaneously. Annealed powders were characterized using X-ray diffractometer (XRD), scanning electron microscope/energy dispersive spectrometer (SEM/EDS) and particle size analyzer. In case of using annealing temperature of 1400°C, VB2-V3B4-V2B3/VC hybrid powders were obtained with an amount of unreacted V2O5. Annealing temperatures of 1500 and 1600°C resulted in the formation of VB2, V3B4, V2B3 and VC phases. Milling affected the weight percentages of the phases as well as the type of major boride phase.

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