Mechanochemical reduction of MoO3/SiO2 powder mixtures by Al and carbon for the synthesis of nanocrystalline MoSi2

In this investigation, MoSi2 intermetallic compound has been synthesized by reducing of MoO3/SiO2 powder mixtures by Al and carbon via mechanical alloying (MA). Powder mixtures were ball milled for 0–100 h and structural evolutions have been monitored by X-ray diffraction. In the Al system, both β-MoSi2 (high temperature phase) and α-MoSi2 (low temperature phase) were obtained after 3 h of milling and after 70 h of milling the β-phase transformed to α-phase. The crystallite size of α-MoSi2 and Al2O3 after milling for 100 h was 12 and 17 nm, respectively. In reducing with carbon, two different compositions with nominal carbon content of 13.7 and 24 wt.% were used that in both compositions, α-MoSi2 forms during 10 h of milling. Higher carbon content increases the amount of MoSi2.