Preparation and Oxygen Separation Property inLa_(0.2)Ba_(0.8)(Co_(0.2)Fe_(0.8))_(1-x)Zr_xO_(3-δ) System

The ceramic oxygen permeation membranes of La0.2Ba0.8(Co0.2Fe0.8)1-xZrxO3-δ with x=0, 0.05, 0.1 and 0.15 were fabricated by a solid state reaction method. The phase structure, microstructure, including morphology, size of crystal grain and second phase in the sample, were investigated by XRD and SEM, respectively. The influence to the properties of oxygen separation and mechanics of samples, caused by microstructure, was also studied. The research results show that the synthesis of single perovskite-structured phase of x=0 by the solid reaction method is difficult, but it can be realized by means of the wet synthesis method or by adding some suitable amounts of ZrO2 into the parent phase. A small amount of BaZrO3 as second phase appeared in the sample with x=0.1 makes the sample possess small crystal grains, with high stability during long time oxygen permeation at high temperature, and larger mechanical strength compared to other composition samples. For the membrane with x=0.1, the oxygen permeation flux can reach to 4.6×10-7mol·cm-2·s-1 at 1010℃ with thickness of 1.2mm under one side exposed to air and the other side feeding with He flow.