Thermal Stability of Thermoelectric Zn4Sb3
The thermal stability of the thermoelectric Zn4Sb3 has been investigated by synchrotron power diffraction measurements in the temperature range of 300 K to 625 K in a capillary sealed under Ar. Data were also collected in air on a 1% Cd-doped sample. Rietveld refinements of the data indicate that a variety of impurity phases are formed. After heat treatment, more than 85% of the Zn4Sb3 phase remains in the 1% Cd-doped sample heated in air, and 97% remains in the undoped Zn4Sb3 heated in Ar. These stabilities are better than those previously observed in pure samples heated in air. This suggests that doping, as well as oxygen or oxidation impurities, play important roles in the thermal stability of this compound.