A study of the effect of aluminum on MoSi2 formation by self-propagation high-temperature synthesis

In this study, the self-propagation high-temperature synthesis (SHS) for the formation of MoSi2 in the presence of aluminum was investigated. Test specimens with nominal compositions including (Mo + 2Si) with stoichiometric ratio and (Mo + 2Si) + 5 wt% Al were employed. Each of the different samples was tested for SHS to determine the thermal profile and differential thermal analysis (DTA) under air atmosphere. The registered thermal profiles resulted for the two samples showed the maximum temperature increase (about 400 °C) in the combustion front in the presence of aluminum. The DTA results also showed that the area of silicon melting point on the DTA curve was deleted in the presence of aluminum. On the other hand, the X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) studies indicated that the SHS reaction between Mo and Si was done in a more complete manner in the presence of aluminum and aluminum particles were all oxidized.