Oxygen diffusion in nanocrystalline yttria-stabilized zirconia: the effect of grain boundaries

The transport of oxygen in dense samples of yttria-stabilized zirconia (YSZ), of average grain size d approximately 50 nm, has been studied by means of 18O/16O exchange annealing and secondary ion mass spectrometry (SIMS). Oxygen diffusion coefficients (D*) and oxygen surface exchange coefficients (k*) were measured for temperatures 673<or=T/K<or=973 at an oxygen partial pressure of 900 mbar. No evidence is found for fast diffusion along grain boundaries. Rather, the analysis indicates that grain boundaries hinder oxygen transport.