Microstructure engineering design for thermoelectric materials : an approach to minimize thermal diffusivity

An alloy engineering approach aiming to produce a fine two-phase mixture thermoelectric material is highlighted in order to reduce the thermal diffusivity. We utilized the spinodal decomposition in the PbTe-GeTe quasi-binary system to control the alloy microstructure through solutioning, quenching and aging treatments. The effect of various microstructural states on the thermal diffusivity is analyzed. It is observed that a minimum in thermal diffusivity is obtained when several microstructural contributions are combined