Microwave sintering and thermoelectric properties of p-type (Bi0.2Sb0.8)2Te3 powder

We report on the use of a modified multimode microwave cavity to sinter commercially available p-type (Bi0.2Sb0.8)2Te3 powder. We have designed a special crucible containing SiC barrels to perform hybrid heating of the samples. Two different initial relative densities were studied (74 and 84%). The morphological evolution of the microstructure was studied by field emission scanning electron microscopy (FESEM). We have also observed that the densification of such powder is possible but that the final relative density reaches an upper limit of 86% due to the formation of Te gas, which results in closed porosity. The Seebeck coefficient was found to be independent of the process. The highest measured power factor is 2.9 × 10− 3 W K− 2 m− 1.