The main activities of Lecco unit of CNR – ICMATE on the subject of thermoelectricity are the material synthesis and the development of new material processing techniques. The development of the activity starts from the synthesis of materials with different techniques ranging from traditional melting to powder metallurgy (mechanical alloying, solid state reactions), going down to powder sintering and material transformation using techniques typical of metallurgy (extrusion, rolling, wiring,…) conveniently set to achieve improved properties in the final samples.

In particular, a new technique, named open die pressing, has been introduced for fast thermoelectric powder sintering. Up to now this technique has been successfully applied on different classes of materials (chalcogenides, silicides, selenides, skutterudites, tetrahedrites) producing materials with characteristics comparable to the best reported in literature.

Bulk ODP

This technique is easy, easily scalable in size obtaining reproducible results and cheap, not requiring special dedicated machinery to be performed. The characteristics of the process, the short time required and the low temperatures involved for sintering, allow the production of nano-structured bulks thanks to the absence of grain/dispersed particles growth. In addition, this process introduces a high texturing degree into the material, allowing, for anisotropic materials, taking advantage, for thermoelectric properties, of the different characteristics as a function of the cutting direction.

A facility for the characterization of standard and customized thermoelectric modules has been realized and is now available to support the development of novel devices. The system works in air and is able to perform characterization with thermal gradients up to 250°C (with hot side up to 350°C).

Calcogenuri 2000X

Calcogenuri 10000X

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Siliciuro 5000X

Siliciuro 20000X