Oxygen permeability in ZrO 2-CeO 2-MgO at high temperatures

Abstract

The oxygen permeability, J o 2 , in CeO 2 doped MSZ, [(ZrO 2) 1 − x (CeO 2) x ] 0.9(MgO) 0.1 ( x = 0.1 ∼ 0.6), was measured at 1100–1750 K under the oxygen partial pressures, P o 2 , of 0.2 − 1 × 10 −4atm. The specimens were predominantly oxide-ion conductors with n-type electronic conduction. The oxygen permeabilities normalized by temperature, T, and P o 2 , log Jr = log [ J o 2 (T(P o 2 II − 1 4 − P o 2 I − 1 4 ) ] , were proportional to 1 T and increased with temperature. At 1100–1500 K, Jr increased exponentially for x ≦ 0.4 and the electronic activation energy, E, was about 2 eV and was independent of x. At 1500–1750 K, Jr increased exponentially for x ≦ 0.4, while for x>0.4 it showed a saturation tendency and the E values were 1.86 ± 0.10 ( x = 0.1), 1.67 ± 0.08 ( x = 0.2), 1.50 ± 0.16 ( x = 0.3), 1.39 ± 0.05 ( x = 0.4), 1.22 ± 0.06 ( x = 0.5) and 1.32 ± 0.04 ( x = 0.6) eV. The log Jr of x = 0.6 was a little higher than that of x = 0.5 at 1100–1280 K ( E = 2.10 ± 0.07 for x = 0.5 and 1.79 ± 0.06 for x = 0.6 eV), while at 1280–1750 K, the value of x = 0.6 was a little lower than that of x = 0.5 ( E = 1.57 ± 0.06 for x = 0.5 and 1.49 ± 0.03 for x = 0.6 eV at 1280–1500 K).