Electrochemical synthesis of vanadium boride powders from their oxide salts

A novel environmentally friendly electrochemical method for synthesizing vanadium boride powders from oxide-based electrolytes was introduced. During this process, co-depositions of vanadium and boron atoms took place on the surface of the low alloyed steel substrates at various stoichiometries, V_xB_y (x≥1; y≥1). The effects of critical electrolysis parameters namely current density (70, 100, 200, 500 mA/cm²), and temperature (900, 950, 1000 °C) were investigated systematically. The X-ray diffraction (XRD) analyses revealed that at low current density (70 mA/cm²) VB is the main phase; whereas, VB₂ became a dominant structure at 100 and 200 mA/cm². However, at high current densities like 500 mA/cm² mixed borides containing VB- V₃B₄- V₂B₃ -VB₂ were detected. The electrolysis temperatures did not cause major variations in the composition of synthesized borides. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) as well as grain size investigations indicated that there is no significant influence of electrolysis conditions on the particle size and it is possible to manufacture high-quality, stoichiometric VB, and VB₂ powders with ≈ 4 µm particle size. The best parameters for producing powders containing primarily VB and VB₂ powders were determined as 1000 °C, 70 mA/cm², and 900 °C, 200 mA/cm², respectively.