MoSi2, (Mo1/2W1/2)Si2, and WSi2 powders were synthesized by self-propagating high-temperature synthesis (SHS)method. The synthesized powders were heat-treated at 500, 1,000, 1,200, 1,300, 1,400, 1,500 and 1,600oC in ambientatmosphere. Oxidation of Mo-W silicide powder was found at low temperature of 500oC. XRD structure analysis and DTA/TG data showed that MoO3 w as f ormed w ith 5 00oC heat treatment for 1 hour, and that it was -cristobalite phase that wasformed with 1200oC heat treatment, not -quartz phase which is commonly found and stable at room temperature.
Existence of W accelerated decomposition at both low and high temperature. Fully sintered MoSi2 and (Mo1/2W1/2)Si2specimen did not show decomposition or weight loss by oxidation, with 1 hour heat treatment at either low or hightemperature. Notably, it was difficult to sinter WSi2 because of oxidation reaction at low temperature.