Self-propagation high-temperature synthesis and casting of Cu–MoSi2 composite

Abstract

Starting from powder mixture of MoO 3 –CuO–Al–Si system, a process of self-propagation high-temperature synthesis and casting (SHS-casting) was employed to fabricate Cu–MoSi 2 composite successfully with assistance of thermit reactions of Al–CuO and Al–MoO 3 . DTA measurements and Gibbs energies change calculations were made to determine sequence of reactions for in situ synthesis of the composite. First, the thermit reaction between Al and CuO took place. The next was the thermit reaction between Al and MoO 3 , followed by a series of reactions in Mo–Si system to form MoSi 2 and Mo 5 Si 3 . Enrichment of Si may aid in depression of transitional phase Mo 5 Si 3 . With an environment of high adiabatic temperatures, silicon got molten. Thus, generation of MoSi 2 may result from a coverage effect of continuous liquid Si to particles of Mo. Due to melting of copper, the Cu–MoSi 2 solidified directionally with an aligned composite structure by means of a steep temperature gradient.