Microestrutura e condutividade elétrica do eletrólito sólido de céria-20%
mol gadolínia com adições de SrO, TiO2
e SrTiO3
Abstract: The effects of SrO, TiO2 and SrTiO3 additions to gadolinia-doped ceria solid electrolyte were systematically investigated. Ceria-20 mol% gadolinia containing 1, 2.5 and 5 mol% of the secondary additives were prepared by mixing of the starting powders followed by solid state reaction at high temperature. Several characterization techniques were used. The results show that the fi nal properties depend on the type and content of the additives. The blocking of charge carriers at the grain boundaries became negligible, but increase of porosity resulted in decrease of the relative density with SrO additions. Densifi cation has been improved with minor amounts of TiO2 , although this additive promoted the exsolution of the dopant from the matrix and consequent formation of the pyrochlore phase Gd2 Ti2 O7 for contents higher than the solubility limit. Additions of SrTiO3 did not infl uence the densifi cation. However, increasing contents of this additive resulted in increase of the intergranular conductivity along with decreasing the activation energy for ion conduction. Keywords: solid electrolyte, ceria, densifi cation, microstructure, electrical conductivity.
Author(s): Dias, M. C. F.; Muccillo, E. N. S.
Cerâmica
Volume: 59 Issue: 352 Pages: 522-532 Published: 2013-12
DOI: http://dx.doi.org/10.1590/S0366-69132013000400006
