Enhancement of self-sustaining reaction by mechanical activation: case of an FeSi system

Mechanical high energy ball milling of an Fe+2Si elemental powders mixture was used to activate a self sustaining combustion reaction or so-called self-propagating high-temperature synthesis (SHS) to form iron disilicide, a reaction for which the thermodynamic criterion is not favorable. A complete characterization of the milled powders before reaction was performed with energy dispersive X-ray spectrometry, specific surface measurements and X-ray diffraction profile analysis. Thermal and structural information describing the combustion front initiated by heating up a sample to 400°C in a Fe–Si system is communicated. In order to isolate the phases involved in the gasless reaction, a time-resolved X-ray diffraction experiment was designed to study in situ the formation of silicide phases (FeSi and β-FeSi 2) produced by the new process called MASHS (mechanically activated self-propagating high-temperature synthesis).