The structural stability and O permeability of Sr3-xLaxFe2-yCoyO7 (where x ranged from 0 to 0.3 and y ranged from 0 to 1) were studied at 800 to 900C, under O partial pressures ranging from 10-5 to 0.21atm. These phases exhibited a perovskite-related intergrowth structure, with tetragonal symmetry, that did not change at temperatures of up to 1000C. The O permeation flux of membranes increased with increasing Co content, decreased with increasing La content, and did not change over time. Measurements of the O permeation flux as a function of membrane thickness, for Sr2.7La0.3Fe1.4Co0.6O7 at 900C, indicated that O transport was bulk-limited at this composition. By assuming that this was also true of other compositions, the ionic conductivity and the vacancy diffusion coefficient were estimated.

Structural Stability and Oxygen Permeation Properties of Sr3-xLaxFe2-yCoyO7. F.Prado, T.Armstrong, A.Caneiro, A.Manthiram: Journal of the Electrochemical Society, 2001, 148[4], J7-14