Large Scale Solid State Synthetic Technique for High Performance Thermoelectric Materials: Magnesium-Silicide-Stannide

We developed a large scale batch synthesis process for the high performance thermoelectric material Mg2Si0.3Sn0.67Bi0.03. An in house liquid-solid reactor was employed to produce ingots of uniform and consistent composition. The ingot material was crushed and sintered under high pressure and temperature into a large 10.2 x 10.2 x 1.0 cm(3) piece for the physical property measurements. Relevant thermoelectric properties were measured on parallelepiped pieces machined at different orientations and positions from the pressed pellet. Large dimensionless figure of merit (zT) values were achieved for all samples, with values greater than zT = 1.2 at 773 K. Statistical analysis revealed consistent material properties, which are necessary for device applications of the given material.