Direct formation of β-FeSi2 in evacuated fused ampoule

A simple preparation method for β-FeSi2 was proposed to activate the interfacial reaction between Fe powder and Si powder through a heat process in a sealed ampoule. The mechanism of the reaction process was investigated by using sputtered Fe films on Si substrates and sapphire substrates. It was found that Si vapor in the ampoule reacts with solid Fe and is saturated to form ε-FeSi. Once ε-FeSi is formed, it initiates the reaction with solid Si to form β-FeSi2.