The equations which governed proton incorporation into oxides were reviewed. Particular attention was paid to high-temperature proton conductors, and SrCe0.95Yb0.05O3 was considered in detail. It was found that various ranges of the key parameters, PH2O and PO2, could be distinguished. Within each of these, essentially one defect type balanced the dopant concentration with regard to the electro-neutrality condition. Transitions between the domains occurred at critical pressures which depended upon the equilibrium constants and dopant concentrations. By introducing new dimensionless variables, it was shown that the entire process of proton incorporation could be described by a single master curve which exhibited Sieverts-type behavior at low H2O pressures, and saturation at high H2O pressures.

T.Schober, W.Schilling, H.Wenzl: Solid State Ionics, 1996, 86-88[1], 653-8