Ultrafast Synthesis and Related Phase Evolution of Mg2Si and Mg2Sn Compounds

Both Mg2Si and Mg2Sn compounds were synthesized by an ultra-fast self-propagating high-temperature synthesis (SHS) method. The data regarding SHS were obtained via theoretical calculation combined with experiments, showing that the adiabatic temperature T (ad) and ignition temperature T (ig) of Mg2Si are a little higher than those of Mg2Sn. The mechanism of phase evolution and the concomitant microstructure evolution during the synthesis process of Mg2Si and Mg2Sn compounds were investigated by adopting SHS technique coupled with a sudden quenching treatment. Differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and x-ray powder diffraction (XRD) results indicate that Mg2Si compound can be directly synthesized through the reaction of Mg and Si elements at around 850 K. Correspondingly, the formation of Mg2Sn needs to undergo melting of Sn and the subsequent feeble reaction between Mg and Sn elements before the large scale transformation at 730 K. As the groundwork, this research embodies great significance for future study on the ultrafast SHS process of the ternary Mg2Si1-x Sn (x) solid solutions.