Low temperature rapid fabrication of magnesium silicide for thermoelectric application

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 degrees C for 5 min without any post-treatment. The pure phase of Mg2Si with grain sizes about 200 nm and with no evidence of presence of MgO was achieved. The Seebeck coefficient, electrical and thermal conductivity were measured to be -220 mu VK-1, 72 Omega(-1)cm(-1)and 3.48 Wm(-1) K-1 at 823 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.