Mechanism of Self-Propagating High-Temperature Synthesis of MoSi<sub>2</sub>

Abstract

The reaction mechanism of self-propagating high-temperature synthesis of MoSi2was investigated by means various methods. The result of activation energy calculation indicates that the synthesis reaction is controlled by a single mechanism. Analysis on the microstructure of Mo/MoSi2and Si/MoSi2interfaces reveals that Mo reacts with Si to directly form MoSi2without any transient product (s). Morphology comparison between the reactants and the product demonstrates that the reaction mechanism is not reactive diffusion. Microstructural observation on the materials from quenched zone shows MoSi2particles precipitate from liquid phase. A mechanism may be proposed based on the above results: Mo particles are covered by molten Si and dissolve into the melt, and then MoSi2particles precipitate from the melt due to super saturation.