Transport and mechanical properties of Yb-filled skutterudites

Abstract

A series of Yb-filled skutterudites were produced and powder samples consolidated using spark plasma sintering (SPS). The effect of different heating cycles on the resulting transport properties of the consolidated samples was explored. Specifically, the effect of sample uniformity on the electrical and thermal transport properties was explored. In addition to the optimal Yb-filling fraction, other factors, such as heating profiles and sintering conditions, were found to play a pivotal role in the performance of these materials. Large quantities of Yb-filled skutterudite material can be generated with high purity and uniformity. Resonant ultrasound spectroscopy was used to determine the elastic modulus and Poisson's ratio. Fracture strength was measured for 12 specimens and, taken with information obtained from resonant ultrasound spectroscopy and from thermal expansion and thermal transport characteristics, the thermal shock resistance parameter was evaluated. These parameters will be important for the engineering of thermoelectric modules based on skutterudite materials.