Thermal Stability Study of Melt Spun TAGS-80 Thermoelectric Bulks

(GeTe)(80)(Ag0.8Sb1.2Te2.2)(20) thermoelectric bulks were fabricated with melt spinning technique. High thermoelectric figure of merit, ZT of 1.78 was achieved at 778 K due to the existence of large density of in-situ nanostructures. The thermal stability of these alloys were highly concerned for practical applications. The thermoelectric properties were measured after annealing these samples under the maximum working temperature of 833 K for 100 h. And the thermoelectric property variation was analyzed by comparing with that of the samples before annealing. It was noticed that after annealing, the electrical conductivity increased and Seebeck coefficient decreased correspondingly. However, most of the nanostructure features could survive the long time annealing process, which suggested that the major phonon scattering mechanism remained, therefore, the phonon thermal conductivity kept consistent. Finally, the ZT values over the entire temperature range were almost the same before and after annealing, which proved the high thermal stability of these bulks.