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Cobalt Gradient Evolution in Sputtered TiNiCuCo Films for Elastocaloric Cooling

Bumke, Lars; Chluba, Christoph; Ossmer, Hinnerk; Zamponi, Christiane; Kohl, Manfred; Quandt, Eckhard

Elastocaloric cooling demands for temperature changes larger than 30 K to become an alternative to classical vapour compression cooling systems. The principle of active regeneration allows to exceed the materials intrinsic adiabatic temperature change. The resulting temperature gradient of the cooling demonstrator leads to a change in the thermomechanical response along the regenerator bed, according to the Clausius–Clapeyron equation. A lowered efficiency as well as an increased probability of early breakdown of the device due to functional and especially structural fatigue are the result. These changes in the thermomechanical response are especially present in NiTi and NiTiCu-based systems with a coefficient math formula of about 7 and 10 MPa K−1, respectively. To address these issues for future applications a change in the transformation temperature along the shape memory alloy film, adapted to the temperature gradient of the regenerator, is required. Cobalt is well known to reduce the transformation temperatures, while maintaining the functional stability of the TiNiCu-based films. In this study multilayer dc-magnetron sputtering is used to fabricate TiNiCuCo films with a cobalt concentration gradient along the samples, which can be precisely tuned by changing the sputter conditions. ... mehr

DOI: 10.1002/pssb.201700299
Zitationen: 5
Web of Science
Zitationen: 4
Zitationen: 5
Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2018
Sprache Englisch
Identifikator ISSN: 0370-1972, 1521-3951
KITopen-ID: 1000078724
HGF-Programm 43.22.01 (POF III, LK 01) Functionality by Design
Erschienen in Physica status solidi / B
Verlag Wiley
Band 255
Heft 2
Seiten Art.Nr. 1700299
Vorab online veröffentlicht am 13.11.2017
Nachgewiesen in Dimensions
Web of Science
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