A comparative study of La0.6Sr0.4Co0.2Fe0.8O3 - δ oxygen transport membranes deposited on porous metal supports prepared by supersonic air-gas plasma spraying (SAPS) and low pressure plasma spraying-physical vapor deposition (PS-PVD)

Perovskite-type La0.6Sr0.4Co0.8Fe0.2O3 - delta (LSCF) oxygen transport membranes were successfully deposited on porous austenitic stainless steel by SAPS. A performance comparison between SAPS membrane and the one prepared by the reported PS-PVD was carried out. X-ray diffraction (XRD) result demonstrates that the degree of perovskite crystallinity of the PS-PVD membrane is better than that of the SAPS membrane. However, scanning electron microscope (SEM) and gas-tightness measurement results indicate that the SAPS membrane shows a much denser microstructure than that of the PS-PVD membrane. The thermal stability result reveals that some vertical through cracks appears on the PS-PVD membrane, while no obvious vertical cracks can be observed on the SAPS membrane. Then the oxygen permeation flux through the membranes was measured under high temperature (700 degrees C and 900 degrees C), It is found that the oxygen permeation flux through the PS-PVD membrane is higher than that of the SAPS membrane. Further studies demonstrate that the oxidation of porous metallic substrates greatly decrease the oxygen permeation flux. (C) 2016 Elsevier B.V. All rights reserved.