Year: 2019
Type: article
Abstract: The stability of the low thermal conductivity in Fe2TiO5 pseudobrookite ceramics has been studied. An increase in thermal diffusivity is observed after only three cycles of measurement. X-ray refraction shows an increase in the mean value of specific surface after the thermal diffusivity measurements. By using scanning electron microscopy and high-angle annular dark-field scanning transmission electron microscope equipped with energy dispersive X-ray spectroscopy, we observe a segregation of Ca- and F-rich nanocrystals at grain boundaries after three cycles of thermal diffusivity measurement. Therefore, impurities seem to be more efficient to scatter phonons as point defects in the pseudobrookite lattice rather than as nanocrystals at pseudobrookite grain boundaries. This emphasizes the importance of precursor purity and the influence of redistribution of impurities on thermoelectric properties: stability of micro-/nano-structures is a key point, and repeated thermoelectric measurements may allow detecting such metastable micro-/nano-structures and producing stable and reliable data.
Source: Materials Characterization
Institutions: Université de Tours, Centre National de la Recherche Scientifique, Federal Institute For Materials Research and Testing, Institut National des Sciences Appliquées Centre Val de Loire, GREMAN, Matériaux, Microélectronique, Acoustique, Nanotechnologies, École Nationale Supérieure d'Ingénieurs de Caen, Laboratoire de Cristallographie et Sciences des Matériaux, University of Potsdam
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,500
OpenAlex ID: W2915063594