Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials

Thermoelectric materials, for example skutterudites and magnesium silicides, are being investigated as promising materials for medium-to-high-temperature waste heat recovery in transport and in industry. A crucial aspect of the success of a thermoelectric material is its stability over time when exposed to rapid heating and cooling. In this work different aspects of the degradation of these thermoelectric materials at high temperature were examined. Initial thermal durability was studied, and several candidate coatings were evaluated to enhance durability by protecting the materials from oxidation and sublimation during thermal cycles in air for up to 500 h and up to 873 K. The samples were characterized by SEM and EDS. The results showed it is possible to reduce degradation of the thermoelectric material without compromising overall thermoelectric efficiency.