COMBUSTION SYNTHESIS OF MOSI2-TIC COMPOSITES

Stability of the binary phases in the quaternary system Mo-Ti-Si-C was examined for the combustion synthesis or Self-propagating High-temper ature Synthesis (SHS) of MoSi2-TiC composites. Thermochemical calculat ions were carried out to obtain the adiabatic temperatures and the amo unts of molten phases at the adiabatic temperature for the SHS of thes e composites. MoSi2-20 wt. % TiC and MoSi2-40 wt. % TiC composites wer e prepared by thermal explosion and SHS modes of combustion from eleme ntal powders. The phase formation was confirmed by x-ray diffraction, and the morphologies were observed under SEM. No general correlation w as obtained between the phase formation or product morphology on the o ne hand, and the adiabatic temperature or the amount of molten phase f ormed at the adiabatic temperature, on the other. MoSi2-40 wt. % TiC c omposites obtained by SHS mode of combustion show a highly homogeneous distribution of the two phases with negligible amounts of ternary pha ses.