Study of Compacting Methods for Nanostructured Thermoelectric Materials Based on Si-Ge and Half-Heusler Alloys.

Recent methods of compacting nanopowders of thermoelectric materials of silicon germanium and Half-Heusler (HH) compounds based on Ni(Ti,Zr,Hf)Sn are presented. Half-Heusler alloys are known to be intermetallic compounds with quite large Seebeck coefficient and semiconducting transport properties. This makes them a potential candidate for thermoelectric applications. In this study we compare compact-ing methods applied to raw materials as a function of crystal structure. The results suggest that the ther-mal conductivity can be reduced by increasing the phonon scattering via nanostructuring. The effect of spark plasma sintering (SPS) and hot pressing on Gleeble system was analyzed by TEM and SEM meth-ods