The oxygen permeation fluxes through solid/melt composite BiVO4 -10 wt % V2O5 membrane have been measured by using the conventional gas flow technique in the temperature range 650-670 degrees C under various oxygen partial pressure gradients. Results indicate that in the range of thickness 0.9-3.5 mm used in the present study, the membrane operates under mixed control of the bulk diffusion and surface exchange kinetics. The ambipolar conductivity, characteristic thickness, and surface exchange coefficient are estimated at values of about 2.8 x 10(-3) S/cm, 0.5 mm, and 5.2 x 10(-6) cm/s, respectively, at 650 degrees C. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3561425] All rights reserved.