Mechanochemical synthesis of MoSi2-SiC nanocomposite powder

MoSi2-25 wt.%SiC nanocomposite powder was successfully synthesized by ball milling Mo, Si and graphite powders. The effect of milling time and annealing temperature were investigated. Changes in the crystal structure and powder morphology were monitored by XRD and SEM, respectively. The microstructure of powders was further studied by peak profile analysis and TEM. MoSi2 and SiC were synthesized after 10 h of milling. Both high and low temperature polymorphs (LTP and HTP) of MoSi2 were observed at the short milling times. Further milling led to the transformation of LTP to HTP. On the other hands, an inverse HTP to LTP transformation took place during annealing of 20 h milled powder at 900 degrees C. Results of peak profile analysis showed that the mean grain size and strain of the 20 h milled powder are 31.8 nm and 1.19% that is in consistent with TEM image. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.