abstract
In this work, brownmillerite-type calcium ferrite (Ca2Fe2O5) ceramics were prepared by two distinct routes, namely by a proteic sol-gel synthesis using commercial flavorless gelatin, and by a solid-state reaction method using mollusk shells. XRD analyses revealed single phase brownmillerite-type calcium ferrites in both cases. SEMEDS analysis of sintered Ca2Fe2O5 ceramics revealed larger grain sizes for the samples prepared via the solid-state reaction. All samples possessed a p-type conduction mechanism, with the largest power factor of similar to 2 mu Wm(-1) K-2 at 450 degrees C observed for the samples obtained via the solid state reaction. The charge transport mechanism was found to depend on the preparation route. The obtained results demonstrated that the proposed synthesis routes can be successfully employed for the preparation of single-phase brownmillerite-type materials.
keywords
THERMOELECTRIC PROPERTIES; MAGNETIC-PROPERTIES; DOPED CA2FE2O5; GRAIN-SIZE; CATHODE; OXIDE; NANOPARTICLES; CONDUCTIVITY; CERAMICS; BEHAVIOR
subject category
Chemistry, Inorganic & Nuclear; Chemistry, Physical
authors
Lima, CGM; Araujo, AJM; Silva, RM; Raimundo, RA; Grilo, JPF; Constantinescu, G; Kovalevsky, AV; Macedo, DA
our authors
Andrei Kavaleuski
Principal Researcher
Gabriel Constantinescu
Researcher
João Paulo de Freitas Grilo
Junior ResearcherProjects
Thermoelectric oxide composites: design through controlled interactions (TEOsINTE)
acknowledgements
This study was financed by CAPES/Brazil, Finance Code 001. Allan Araujo, Joao Grilo and Daniel Macedo acknowledge CNPq/Brazil (200439/2019-7, 431428/2018-2 and 309430/2019-4). Gabriel Constantinescu acknowledges the support of the TEOsINTE project (Grant agreement ID: 101003375), funded under H2020-EU.4. (Funding Scheme: MSCA-IF-EF-ST -Standard EF). This research was also funded by the projects REMOTE (POCI-01-0145-FEDER-031875), CICECO-Aveiro Institute of Materials (UIDB/50011/2020 and UIDP/50011/2020), financed by COMPETE 2020 Program and National Funds through the FCT/MEC and, when applicable, co-financed by FEDER under the PT2020 Partnership Agreement.