A combination of isotopic exchange depth profiling and low-energy ion-scattering and elastic recoil detection analysis had revealed a complex structure which affected the surface O exchange reactions and self-diffusion in 10mol%yttria-doped zirconia. A thin (about 6nm) layer at the external surface resembled the monoclinic phase. The results suggested that there would be a significant improvement in the surface O exchange, with respect to published values, when impurity oxides were prevented from segregating to the external surface. Reported improvements in the surface O exchange by the addition of a surface catalyst were also attributed to the removal of impurities.

Oxygen Exchange and Diffusion in the Near Surface of Pure and Modified Yttria-Stabilised Zirconia. M.de Ridder, R.G.van Welzenis, H.H.Brongersma, U.Kreissig: Solid State Ionics, 2003, 158[1-2], 67-77