Electrical assessment of brownmillerite-type calcium ferrite materials obtained by proteic sol-gel route and by solid-state reaction using mollusk shells

authors	Lima, CGM; Araujo, AJM; Silva, RM; Raimundo, RA; Grilo, JPF; Constantinescu, G; Kovalevsky, AV; Macedo, DA
nationality	International
journal	JOURNAL OF SOLID STATE CHEMISTRY
author keywords	Ca2Fe2O5; Proteic sol-gel synthesis; Solid-state reaction; Mollusk shells; Electrical properties
keywords	THERMOELECTRIC PROPERTIES; MAGNETIC-PROPERTIES; DOPED CA2FE2O5; GRAIN-SIZE; CATHODE; OXIDE; NANOPARTICLES; CONDUCTIVITY; CERAMICS; BEHAVIOR
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.
publisher	ACADEMIC PRESS INC ELSEVIER SCIENCE
issn	0022-4596
isbn	1095-726X
year published	2021
volume	299
digital object identifier (doi)	10.1016/j.jssc.2021.122172
web of science category	7
subject category	Chemistry, Inorganic & Nuclear; Chemistry, Physical
unique article identifier	WOS:000647792400022