Process Scalability for Promising Si Based Thermoelectric Materials

For medium temperature applications, magnesium silicide stannide and manganese silicide (HMS) are considered as the most promising thermoelectric materials. The scale-up of these materials was performed by gas phase atomization for powder production, followed by Spark Plasma Sintering process in a pre-industrial scale technological platform for thermoelectrics “PAMIRE” (Grenoble, France). Kilograms batches of thermoelectric powder were processed, leading to the production of a large quantity of homogenous 60 mm diameter silicide pellets.The development of high performance materials was obtained by a deep investigation on the relation between thermoelectric properties and material microstructure. During the synthesis process nano/micrometric precipitates were formed. TEM analysis and thermoelectric measurements were systematically correlated. The figure of merit of the produced material reaches ZT_max of 1.4 and 0.54 for n-type and p-type materials respectively.Moreover, promising assembly processes for thermoelectric modules were initiated. The performances of first silicide modules produced by CEA-LITEN thermoelectric lab were measured on a specific bench, in conditions representative of applications (temperature and heat flux).