Síntese e caracterização de cerâmicas do tipo BZYO e BCGO para uso em células a combustíveis
Carregando...
Data
2014-04-11
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
The study of the synthesis of materials which have proton conductivity
contributes to the production of solid electrolytes protonic conductors, used extensively
in the operation of fuel cells. Materials doped barium zirconate yttrium (BZYO) and
barium cerate doped with gadolinium (BCGO), were synthesized by the polymeric
precursor method, which stands as an effective technique. The synthesized powders
were characterized by thermal analysis (TG-DTA), X-ray Diffraction (XRD), Scanning
Electron Microscopy (SEM / FEG) and Zeta Potential. The sinterability of the powders
was observed by dilatometric analysis, followed by XRD, SEM / FEG and density
apparent. From the results obtained it was possible to verify the formation of BZYO
phase at a temperature of 900 °C/ 2h. A higher dopant concentration (20% Y) promoted
the formation of the phase in a temperature 800 °C/ 2h, and the formation of the phase
BCGO at 950 °C/ 2h. The crystallite size calculated by Scherrer's equation, ranged from
20,8 to 15,2 nm and 38,2 to 30,5 nm for BZYO and BCGO respectively. This results
depends on the amount of dopant and its capacity to form solid solution. The
micrographs (SEM/FEG) confirmed the nanometric nature of the material with a
spherical morphology. The zeta potential was -23,6 mV and -22,8 mV for BZYO and
BCGO, respectively, which demonstrates a good stability in the formation of colloidal
dispersions for thin film formation which are of interest for fuel cells. The pads BCGO
showed a satisfactory densification (95,1%) at 1550 °C/ 4h, a result that shows its
applicability as proton conductive solid electrolyte. For tablets BZYO the densification
was lower than BCGO with a result of bulk density of 73,8% at 1600 °C/ 4h. This result
shows the need for heat treatment at higher temperatures to obtain a higher densification
of the pellets.
Descrição
Palavras-chave
Cerâmicas, Células a combustível, Nanotecnologia, Precursores poliméricos, Ceramics, Full cell, Nanotecnology, Polimeric precursor method
Citação
BORGES, K. C. M. Síntese e caracterização de cerâmicas do tipo BZYO e BCGO para uso em células a combustíveis. 2014. 91 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Catalão, 2014.