IONIC TRANSPORT IN SrCo_0.855Ti_0.15O_3-δ CERAMICS AT HIGH OXYGEN PRESSURES

摘要

Oxygen permeation through dense ceramic membranes of the SrCo_0.85Ti_0.15O_3-δ cubic perovskite solid solution was studied in the range of the membrane feed-side oxygen partial pressures (p_2) 0.2l to l00 atm at temperatures of 850--l040 K. The dependence of the oxygen fluxes on membrane thickness suggests that bulk ionic conductivity is the permeation- determining factor at high oxygen pressures (p2 > to l atm). Increasing the oxygen pressure up to 80--l00 atm was found to result in a drastic increase of the permeation flux, accompanied by a partial decomposition of the cubic perovskite phase of Sroo_0.85Ti_0.15O_3-δ, forming two isostructural perovskite- type phases. No phase changes were observed after testing ceramics in the oxygen pressure range of l-60 atm. The high oxygen permeation fluxes obtained demonstrate the applicability of SrCo_0.85Ti_o.5O3-δ membranes at high oxygen pressures.