New p- and n-type skutterudites with ZT>1 and nearly identical thermal expansion and mechanical properties

• Published in: Acta materialia Vol. 61; no. 11; pp. 4066 - 4079
• Main Authors: Rogl, G., Grytsiv, A., Royanian, E., Heinrich, P., Bauer, E., Rogl, P., Zehetbauer, M., Puchegger, S., Reinecker, M., Schranz, W.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2013; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; High-pressure torsion; Intermetallics; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nanomaterials; Skutterudites; Mechanical properties; Intermetallics; Nanomaterials; Skutterudites; High-pressure torsion; Thermal properties; Thermal expansion; Intermetallic compound; Expansion; Torsion
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2013.03.031

Using thermoelectricity to directly convert (waste) heat energy into useful electricity faces a number of challenges. Not only are optimised thermal and electrical transport properties required resulting in a high figure of merit ZT and a high thermal–electric conversion efficiency η over a wide temperature range, thermoelectric (TE) materials must have sufficient mechanical integrity to survive continuous heating–cooling cycles. Thermal expansion of the material as well as the mechanical properties play an important role, i.e. their values should be as similar as possible for p- and n-type alloys to avoid stresses when used in a TE device. In this paper multiple filled p- and n-type skutterudites (Ba,Sr,DD,Yb)y(Fe1–xNix)4Sb12 with a ZT>1 and η≈13% are presented, for the first time showing, in contrast to hitherto investigated skutterudites, nearly identical thermal expansion coefficients and elastic moduli. The ZT values of these skutterudites could be further enhanced by more than 20% after severe plastic deformation via high-pressure torsion.