Abstract：Co element was added into Gd-doped ceria (GDC) powders by two methods namely lattice solution and preferred grain boundary segregation, respectively. The 10% (mole fraction, the same below) Gd-doped ceria (10GDC) solid solution powders were co-precipitated and then doped with 1%Co by the means of the two ways. These powders were named as 10GDC-1Co (SS) and 10GDC-1Co (GBS), respectively. Then the powders above were sintered at 1000℃ for 1h to obtain 10GDC, 10GDC-1Co (SS) and 10GDC-1Co (GBS) ceramic samples. All the synthesized powders and sintered samples only consist of the CeO2 solid solution phase, and their grain sizes are 10.1-12nm and 59.8-112nm, respectively. The conductivities of 10GDC-1Co (SS) and 10GDC-1Co (GBS) samples are higher than that of 10GDC samples. When the test temperature is lower than 430℃, the conductivities of 10GDC-1Co (GBS) samples are higher than that of 10GDC-1Co (SS) samples, but as the test temperature increases, the conductivities of 10GDC-1Co (GBS) samples are lower than that of 10GDC-1Co (SS) samples.
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