It was recalled that 2 steps governed O transport in ceramic oxide ion conductors. One was O exchange at the surface of the material and the other was O diffusion through the material. The 18O/16O isotope-exchange depth profile technique was applied here to BIMEVOX materials in order to characterize O transfer in these ceramics. The isotope concentration profiles, as obtained by secondary ion mass spectrometry, revealed that the equilibrium exchange kinetics in BIMEVOX materials in nominally dry O were dominated by a relatively slow surface-exchange step. This produced deep penetration profiles, with very low isotopic concentrations that were close to the natural isotopic background. The O surface-exchange coefficient in these materials was of the same order of magnitude as that in traditional oxide electrolytes such as ceria-gadolinia and yttria-stabilized zirconia. Transfer of O from water was much easier. This made the accurate determination of the true coefficient of exchange of molecular O in these materials more complicated; due to residual water.

Oxygen Transfer in BIMEVOX Materials. R.N.Vannier, S.J.Skinner, R.J.Chater, J.A.Kilner, G.Mairesse: Solid State Ionics, 2003, 160[1-2], 85-92