A study on mechanochemical behavior of MoO3–Mg–C to synthesize molybdenum carbide

• Published in: International journal of refractory metals & hard materials 2014-11, Vol.47, p.18-24
• Main Authors: Torabi, Omid, Golabgir, Mohammad Hossein, Tajizadegan, Hamid, Torabi, Hamid
• Format: Article
• Language: English
• Subjects: Carbothermal reduction; Magnesiothermic reaction; Mechanochemical synthesis; Molybdenum carbide; Thermal analysis
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2014.06.001

The influence of Mg value in the MoO3–Mg–C mixture on the molybdenum carbide formation and the mechanism of reactions during mechanochemical process were investigated. In keeping with this aim, magnesium and carbon contents of the mixture were changed according to the following reaction: 2MoO3+(6−x) Mg+(1+x) C=(6−x) MgO+Mo2C+x CO. The value of x varied from 0 to 6. Differential thermal analysis (DTA) results for sample with stoichiometric ratio (x=0) revealed that in the early stage, carbon reduced the MoO3 to MoO2 and subsequently highly exothermic magnesiothermic MoO2 reduction occurred after magnesium melting. Also, it was indicated that the exothermic reaction temperature shifted to before magnesium melting in the 11h-milled sample (x=0) and all the exothermic reactions happened, simultaneously. According to the experimental findings, molybdenum carbide (Mo2C) was synthesized in the mixture powder with stoichiometric ratio (x=0) after 12h milling process and the type of reactions was mechanically induced self-sustaining reaction (MSR). However, at lower Mg content in the MoO3–Mg–C mixture (0