Transport Properties and Microstructural Evolution of Bi-Cu-Te Ternary Alloys

Abstract

The widening gap between energy demand and production has created an energy gap in the developing nations. This gap is met by increasing the energy production using fossil fuel-based methods but they come at the cost of rising CO2 levels in the environment. Thus, alternative green energy sources have to explored to fulfill the energy demands. In this regard, thermoelectric materials play an important role as they convert waste heat into useful energy. In the current study, authors have presented a detail study on Bi-Cu-Te thermoelectric alloys. Alloy compositions were selected using a self-consistent thermodynamically optimized database of the Bi-Cu-Te, then microstructure evolution and the thermoelectric properties of several alloys were evaluated. Microstructure features in the alloys showed the formation of eutectic ( [[EQUATION]] and [[EQUATION]] ) along with primary phases depending on the composition. Developed microstructures was explained using thermodynamic and Scheil cooling calculations. The electric conductivity of the optimized alloy was observed to be 90kS/m, Seebeck coefficient [[EQUATION]] , and power factor [[EQUATION]] at 480 K. It was also observed that the γCu3Te2 increase (two times) the hardness of the Bi2Te3 alloys. The current approach of combined theoretical and experimental methods can be utilized for development of novel thermoelectric materials.

Keywords: Transport properties, thermoelectric, Bi-Cu-Te, electrical conductivity, Ternary Eutectic