abstract
This work reports the microstructural and thermoelectric characterization of the misfit [Ca2CoO3-delta](0.62)[CoO2] compound obtained by a solid-state synthesis using mollusk shells and a proteic sol-gel method, which uses gelatin as a polymerizing agent. The results clearly demonstrate the capability of these routes to produce pure Ca3Co4O9 with plate-like morphology. Sintered ceramic samples show randomly oriented grains and relative densities in the range of 63-67%. The obtained microstructures provide reasonable electrical properties and result in competitive thermoelectric performance for the material prepared by the proteic sol-gel synthesis (P.F. of 205 mu W/K-2 m at 700 degrees C). (C) 2019 Elsevier B.V. All rights reserved.
keywords
CA3CO4O9 CERAMICS; COBALT OXIDE; MICROSTRUCTURE; ENHANCEMENT; PERFORMANCE; CA; BEHAVIOR; C349
subject category
Materials Science; Physics
authors
Emerenciano, AA; Araujo, AJM; Grilo, JPF; Macedo, DA; Rasekh, S; Kovalevsky, AV; Paskocimas, CA; Nascimento, RM
our authors
acknowledgements
This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) - Finance Code 001. Daniel A. Macedo acknowledges CNPq (Brazil, 311883/2016-8 and 431428/2018-2). The authors also acknowledge the support of FCT, Portugal with SFRH/BPD/124238/2016 grant, and UID/CTM/50011/2019 and POCI-01-0145-FEDER-031875 projects, financed by COMPETE 2020 Program and National Funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement.