Low temperature rapid fabrication of magnesium silicide for thermoelectric application

Abstract

A mechanism for rapid, single-step synthesis and fabrication of intermetallic compounds having brittle–ductile ingredients at low temperature is suggested. Employing this mechanism, highly pure, dense Mg2Si pellets were obtained using silicon nanoparticles and micron-sized magnesium particles as starting materials. Silicon nanoparticles chop magnesium particles and produce highly-activated mixture through a planetary ball-milling. Magnesium/silicon interface increases by increasing dispersity of silicon nano-particles in magnesium. Consequently, final product was prepared only by consolidation at 300∘C for 5[Formula: see text]min without any post-treatment. The pure phase of Mg2Si with grain sizes about 200[Formula: see text]nm and with no evidence of presence of MgO was achieved. The Seebeck coefficient, electrical and thermal conductivity were measured to be [Formula: see text]220 [Formula: see text]VK[Formula: see text], 72 [Formula: see text][Formula: see text]cm[Formula: see text] and 3.48[Formula: see text]Wm[Formula: see text][Formula: see text]K[Formula: see text] at 823[Formula: see text]K for nondoped Mg2Si, indicating that this method does not degrade the properties of the product, despite the fact that fabrication is performed rapidly and at low temperature.