Transport properties of ceria–zirconia–yttria solid solutions {(CeO2)x(ZrO2)1−x}1−y(YO1.5)y (x = 0–1, y = 0.2, 0.35)

The electron and hole conductivity, oxygen transport property and thermal expansion behavior of {(CeO 2 ) 0.5 (ZrO 2 ) 0.5 } 0.65 (YO 1.5 ) 0.35 solid solution were investigated and the effect of yttrium content was examined by comparing the data with those of {(CeO 2 ) 1-x (ZrO 2 ) x } 0.8 (YO 1.5 ) 0.2 . The electron conductivity of {(CeO 2 ) 0.5 (ZrO 2 ) 0.5 } 0.65 (YO 1.5 ) 0.35 measured by ion blocking method was one order lower than that of {(CeO 2 ) 0.5 (ZrO 2 ) 0.5 } 0.8 (YO 1.5 ) 0.2 . The increase of yttrium content suppressed the phase transition from cubic to pyrochlore structure in reducing atmosphere. The oxygen isotope diffusivity and surface exchange rate constant of {(CeO 2 ) 0.5 (ZrO 2 ) 0.5 } 0.65 (YO 1.5 ) 0.35 are considered to be comparable to those of {(CeO 2 ) 0.5 (ZrO 2 ) 0.5 } 0.8 (YO 1.5 ) 0.2 . The chemical expansion due to the reduction of cerium ion was observed as well as for rare earth doped ceria. The compatibility of the material as an anode substrate in solid oxide fuel cells is discussed.