Oxygen surface exchange in mixed ionic electronic conductor membranes

We discuss the different oxygen surface exchange coefficients and the net surface exchange flux i = c(i)k(i0)[exp(n mu(8)/RT) - exp(2n mu/RT)] at gas-MIEC oxide interfaces, where k(i) = k(i0)(p/p(0))(n) is the surface exchange coefficient, derived from isotope exchange experiments, p is the oxygen pressure, mu(s) and mu are the chemical potentials of the gas and of the ion-electron hole pairs at the interface and c(i) is the oxygen ion concentration. The model is applied to oxygen permeation in planar and tubular membranes. (C) 1999 Published by Elsevier Science B.V. All rights reserved.