Özet:
Sm2O3, Gd2O3, Eu2O3 triple-doped Bi2O3 based quaternary solid solutions were synthesized as a
candidate electrolyte material using the solid-state reaction technique. The structural, thermal
and electrical conductivity features of the ceramic samples were examined and compared by
using X-ray powder diffraction (XRD), thermal gravimetry/differantial thermal analysis (TG/
DTA) and the four-point probe technique (4PPT). The result of XRD measurements indicated that
the (Bi2O3)(1−x−y−z)(Gd2O3)x(Sm2O3)y(Eu2O3)z (x = 10/y = 10/z = 5, 15, 20 mol % and
x = 10/y = 5, 10, 15, 20/z = 10 mol %) samples have a stable face-centered cubic δ-phase and
mixed phase crystallographic structure. The phase stability was also checked by the DTA eva luations results. The temperature dependent electrical conductivity measurements showed that
the highest electrical conductivity was observed for the sample of the
(Bi2O3)0.75(Gd2O3)0.10(Sm2O3)0.05(Eu2O3)0.10 system which has a stable and δ-phase was found
as 6.67 × 10−3 (Ω cm)−1 at 650 °C. This sample can be used as an electrolyte material in the
solid oxide fuel cells (SOFCs) which is possible to operate at intermediate temperature ranges.
The activation energy was also calculated at a low temperature range (350–650 °C) and high
temperature range (above 650 °C). The values for the samples vary from 0.63 eV to 1.08 eV at
low temperature and at high temperature they vary from 0.43 eV to 0.75 eV.