Solid-state synthesis of magnesium base thermoelectric alloys via bulk mechanical alloying

Magnesium binary and ternary alloy systems have been popular as a thermoelectric light-weight alloy to be working in the medium temperature range. The solid-state reactivity via the bulk mechanical alloying is applied to yield these types of alloys. The diffusion-controlled solid-state synthesis is first stated as a process to yield a binary compound, Mg:X (X = Ge, Sn and Pb). This processing is further applied to directly synthesize several ternary thermoelectric alloys Mg₂Si_1-xGe_x, Mg ₂Si_1-ySn_y and Mg₂Sn _1-zPb_z for 0.0 < x, y, z < 1.0 and to evaluate their thermoelectric properties. Hot pressing is used to make full-dense billets and samples for thermoelectric measurement. The effect of germanium and tin contents on their Seebeck coefficient and band-gap is investigated to describe the p-n transition behavior and to understand the change of electric structure with solid solution formation.