The O flux through yttria-stabilized zirconia with LaCrO3, Gd-doped ceria + LaCrO3 (bilayer), LaCrO3 + 5wt%Gd-doped ceria (mixture), or LaCr0.7Co0.3O3 coatings were measured under controlled PO2 gradients (permeate-side PO2: 3 x 10−12atm, feed-side PO2: 2 x 10−10 to 2 x 10−8atm) at 1600C. The O flux increased markedly due to these coatings. The highest increase in O flux was found for Gd-doped ceria + LaCrO3 (bilayer) coatings and was maintained for a long time. The presence of highly catalytic Ce ions, and a porous structure of the coating layer was suggested to explain the effect. The prevention of the formation of a resistive layer due to the ceria coating was also suggested to be partly responsible for the observation.

Oxygen Permeation Characteristics of Zirconia with Surface Modification. H.J.Park, G.M.Choi: Solid State Ionics, 2006, 177[26-32], 2261-7