Abstract
High ZT thermoelectric materials are obtained by a good knowledge of the materials involved in their fabrication. The phase transformations and phase stabilities of new materials are still unknown; consequently, a thermodynamic study of these systems is needed. The development of thermodynamic and kinetic databases of such practical materials is important for the microstructural evolution of the materials during processing and service for improving the knowledge. In this paper we will present some peculiarities of this materials at the light of a phase diagram analysis and show finally how the Calphad method is necessary to study such multicomponent materials and to determine the best synthesis process (single crystals growth, powder metallurgy,...). Exemples of advanced thermoelectric materials taken is this paper are: Pb1-xSnxTe Zn4Sb3 and Co4-xNixSb12. They are studied from a thermodynamic point of view and we will show the relationships between calculated phase diurnal, microstructure constitution and processes.