Simple fabrication of Mg2Si thermoelectric generator by spark plasma sintering

277-280Raw Mg and Si powders have been used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering (SPS). The optimum parameters to synthesize pure Mg2Si are found to be 823 K-0 MPa-10 min with excessive content of 10wt% Mg from the stoichiometric Mg2Si. Mg2Si bulk has been firstly synthesized and densified simultaneously at low temperature (823 K) and high pressure (higher than 100 MPa) from the raw powder, but Mg and Si not react completely, and the sample is not very dense with some microcracks on the surface. Then, Mg and Si powders firstly reacted at 823 K-0 MPa-10 min in SPS chamber to form Mg2Si green compact, again sintered by SPS at 1023 K-20 MPa-5 min. The fabricated sample only contained Mg2Si phase with high relative density (nearly 100%)