Synthesis of MoSi2–Al2O3 nanocomposite by mechanical alloying

MoSi2–Al2O3 nanocomposite was synthesized by mechanical alloying (MA) of MoO3, SiO2 and Al powder mixture. The structural evolution of the powders was studied by X-ray diffraction (XRD). Both β-MoSi2 and α-MoSi2 were obtained after 3 h of milling. The spontaneous formation of β-MoSi2 during milling proceeded by a mechanically induced self propagating reaction (MSR), analogous to that of the self propagating high temperature synthesis (SHS). 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. Residual Mo and Si in the 3 and 70 h milled samples formed β-MoSi2 and Mo5Si3 during heating at 1000 °C, respectively.