It was found that H permeated the bulk of the fluorite-type solution, (CeO2)0.9(CaO)0.1, at 1075 to 1800K. Two tubular specimens of differing lengths were prepared. The source gas, N2-7.8%N2, was humidified at 293K and was supplied to the outside of the specimens, while Ar was allowed to flow to the inside of the specimens. The permeated H in the outlet Ar gas was analyzed by using a gas chromatograph. The Arrhenius plot of the permeability was almost straight. The gradient of the line changed at 1525K. The activation energy for conduction was estimated to be 1.07eV above 1525K, and 0.73eV below 1525K. The activation energy which was determined from the O permeability was higher than these values, and was suggested to be the activation energy of protons. It was possible that the present material was a mixed conductor in H2-H2O atmospheres at high temperatures.

Hydrogen Permeability in (CeO2)0.9(CaO)0.1 at High Temperatures. Y.Nigara, J.Mizusaki, K.Kawamura, T.Kawada, M.Ishigame: Solid State Ionics, 1998, 113-115, 347-54