Thermal and mechanical stability of microwave sintered cold compact bismuth telluride thermoelectric material

Both p-type and n-type bismuth telluride (Bi2Te3)-based thermoelectric materials demonstrate high thermoelectric efficiency in the low-temperature thermoelectric modules, but their constrained thermal and mechanical stability restrict their commercial applications. In our current work, we report the thermal and mechanical properties of both p-type and n-type bismuth telluride-based thermoelectric materials prepared by the cold compaction method. The compacted pellets were sintered in a microwave at 250 degrees C and 300 degrees C. Thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC) analysis were performed to study the thermal stability, and nanoindentation, compression test, and microhardness tests were done for mechanical stability. The TGA-DSC results indicate a slight mass gain at 350 degrees C followed by a steep weight loss beyond 550 degrees C suggesting good thermal stability when the experimental temperature is below 350 C. The hardness values decreased with an increase in the sintering temperature. The compression strength for all the samples had almost a constant value of 64 +/- 0.5 MPa. Our fabrication method has the benefits of a low-cost, simple, and quick process paired with better thermal and mechanical properties, making it a good prospect for bismuth telluride thermoelectrics.

Automated summary

Both p-type and n-type bismuth telluride-based thermoelectric materials show high thermoelectric efficiency in low-temperature thermoelectric modules, but their thermal and mechanical stability restrict their commercial applications. In this study, we report the thermal and mechanical properties of these materials prepared by the cold compaction method. The results show good thermal stability below 350°C and consistent compression strength for all samples.