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.
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.
The laboratories are equipped with facilities specific for materials characterization: structural analyses (XRD in temperature between -150°C and 1200°C), microstructural (optical and electronic microscopy), thermal analyses and thermoelectric properties (Seebeck, electrical conductivity in the range between -200°C and 450°C) (See tabs Laboratories for ICMATE-LC).
Looking at the technological applications of thermoelectricity, the focus is the study of devices for power generation from wasted heat recovery. Strategic developments are addressed to the coupling of thermoelectric technology to catalytic combustion, aiming for generators able to be interfaced to modern portable/mobile technologies. Prototypes of generators coupled with different systems have already been produced following the requirements of industrial partners.
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).
thermoelectricity sintering heat recovery materials processing
L. Merotto, C. Fanciulli, R. Dondè, S. De Iuliis
Study of a Thermoelectric Generator based on a Catalytic Premixed Meso-scale Combustor
Applied Energy 162 (2016) 346
A. Castellero, C. Fanciulli, R. Carlini, G. Fiore, P. Mele, F. Passaretti, M. Baricco
Effect of processing routes on the synthesis and properties of Zn4Sb3 thermoelectric alloy
Journal of Alloys and Compounds 653 (2015) 54
C. Fanciulli, S. Battiston, S. Boldrini, E. Villa, A. Famengo, S. Fiameni, M. Fabrizio, F. Passaretti
Fast sintering of thermoelectric silicide powders using Open Die Pressing technique
Materials Today: Proceedings 2 (2015) 566
S. Ceresara, C. Fanciulli, F. Passaretti, D. Vasilevskiy
Texturing of (Bi0.2Sb0.8)2Te3 nanopowders by Open Die Pressing
Journal of Electronic Materials 42 (2013) 1529
C. Fanciulli, M. Codecasa, F. Passaretti, D.Vasilevskiy
Effects of Metal Particles Decoration on n-type Chalcogenides Processed by Open Die Pressing
Journal of Electronic Materials 43 (2014) 2307
- L. Merotto, C. Fanciulli, R. Dondè, S. De Iuliis