Targeted Use of SPS Method for Improvement of Thermoelectrics

Abstract

Use of spark plasma sintering (SPS) allows improving thermoelectric figure of merit Z of bulk nanothermoelectrics but required parameters of SPS process for achievement of best Z can be defined only empirically.
In the present study the finite elements method for investigation of electric and thermal processes which occur in volume and on boundaries of sintering particles is applied. As a geometrical model a structural cell of a sintered sample, containing contact “a truncated cone - a plate” has been chosen. Temperature distributions in the volume of a sample depending on amplitude, on-off time ratio and duration of impact of the electric current has been obtained for solid solution based on bismuth telluride using the energy balance equation and the equation of electric current continuity. Under certain conditions nonlinear and nonlocal processes start to arise.
The calculated temperature distributions at different sintering conditions were comparing with empirically defined experimental parameters that lead to improved value of Z. The comparison allows formulating recommendations to achieve best conditions of SPS process for increase of Z. The present method can be used for management of SPS fabrication process for different application, not only for thermoelectrics.