In situ observation of eutectoid reaction forming a PbTe-Sb_2Te_3 thermoelectric nanocomposite by synchrotron X-ray diffraction

摘要

In situ high-temperature powder X-ray diffraction experiments have been performed on Pb_(10.5)Sb_(31.6)Te_(57.9) using a synchrotron X-ray source to observe the eutectoid reaction from Pb_2Sb_6Te_(11) to PbTe and Sb_2Te_3. Molar fractions of the constituent phases and fraction transformed were obtained as functions of time. The experimental fraction transformed vs. time curve were well fitted by the Kolmogorov-Johnson-Mehl-Avrami equation with an Avrami index n=1.4. The small n value suggests that the growth of the new phases PbTe and Sb_2Te_3 is one-dimensional.