Preparation of an asymmetric perovskite-type membrane and its oxygen permeability

A crack-free asymmetric membrane of perovskite-type oxide (La0.6Sr0.4Co0.2F e0.8O3-delta) was successfully prepared by coating a slurry containing La0. 6Sr0.4Co0.2Fe0.8O3-delta powders directly on the surface of a green support of the same composition, followed by sintering. It was found that crack-fo e asymmetric membranes could be obtained by controlling the powder concentr ation of the slurry in the range of 15-25 wt.% After sintering, the crystal phase of the top layer of asymmetric membranes prepared was the same as th at of powders, which were of the cubic perovskite phase. The nitrogen perme ability and SEM photograph of the support showed that the support was porou s, and the gas-tight test and SEM demonstrated that the top layer of asymme tric membrane was dense and crack-free. The asymmetric membrane prepared, w hose dense top layer was 200 mum thick, exhibited about three to four times as high an oxygen flux as a 2 mm dense sintered disc. (C) 2001 Elsevier Sc ience B,V. All rights reserved.