Synthesis and Characterization of the Composite Co/VC Nano Powder by Mechanochemical Method and Investigating the Reaction Thermodynamic Behavior

In the present study, production of the composite nano powder of Co/VC by mechanochemical method from Co3O4, V2O5, and graphite as the starting materials with magnesium as the reduction agent was investigated. For this purpose, the materials powder mixture was milled in accordance with stoichiometric reaction in a high energy ball mill with the ball-to-powder ratio of 20:1 under argon atmosphere for different durations. After 10min of milling, combustion occurred and the XRD results indicated that magnesium has reduced vanadium and cobalt oxides (V2O5 and Co3O4) and has changed into magnesium oxide; also, graphite has reacted with the metallic vanadium to form vanadium carbide, which means that the reaction has been completed. Based on the adiabatic temperature of the reaction (Tad~ 3932.014), the reaction was identified as a mechanically inducted self-sustaining one or MSR. The crystallite sizes of vanadium carbide and cobalt calculated by the Williamson-Hall equation were 50 and 10nm, respectively. Finally, the magnesium oxide phase was deleted from the system via leaching process in 0.9% hydrochloric acid and the composite powder of Co/VC was obtained.