The difference of synthesis mechanism between Ti3SiC2 and Ti3AlC2 prepared from Ti/M/C (M=Al or Si) elemental powders by SHS technique

Ti3MC2 ternary compounds (M=Al or Si) have been prepared by a self-propagating high-temperature synthesis (SHS). The difference of synthesis mechanism between Ti3SiC2 and Ti3AlC2 using Ti/M/C(M=Al or Si) powder mixtures and some TiC or some intermetallic compounds as raw materials has been investigated. The phase composition and the relative content of Ti3MC2 materials in the final products were determined by X-ray diffraction (XRD). The results show that TiC and intermetallic compounds of TiAl have played an important role in synthesis of Ti3AlC2. The relative content of Ti3AlC2 in the products increases with increased addition of TiC or TiAl in the raw materials. In contrast, the relative content of Ti3SiC2 in the products changes less with increasing of TiSi2 content, even decreases with increasing of TiC content in the raw materials. The difference of synthesis mechanism between them has been explained thermodynamically.