Effect of Segregation on Surface and Near-Surface Chemistry of Yttria-Stabilized Zirconia

The present work reports the effect of segregation on surface and near-surface composition of yttria-stabilized zirconia, YSZ. The study included the determination of the effect of both temperature (1073-1673 K) and oxygen activity (10(-10) Pa < p(O-2) < 75 kPa) on segregation-induced concentration profiles of yttrium. The secondary ion mass spectrometry, SIMS, was applied to determine the chemical composition of the outermost surface layer as well as the layers beneath the surface. It is shown that the effect of oxygen activity on the segregation-induced enrichment of yttrium is substantial in the temperature range 1073-1473 K. The maximum of enrichment in yttrium is observed at 1273 K. The segregation-induced enrichment of YSZ is considered in terms of a low-dimensional surface structure that is formed due to surface enrichment in both yttrium (dopant) and silicon (impurity). The effect of the surface and near-surface chemistry on the performance of YSZ-based energy conversion devices is discussed.