Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.
DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.
The effect of the bulk microstructure (grain size distribution, grain boundary composition on the oxygen transport properties of La0.5Sr0.5FeO3membranes was investigated. For this purpose, samples with different microstructures were prepared by modifying the sintering duration and/or temperature. The average grain sizes, ranging from 0.20 to 1.43μ m, were determined from SEM analysis. The oxygen transport properties of the samples were characterised by permeation measurement. The fluxes presented a change in the activation energy which was attributed to a change in the rate limiting step, from bulk diffusion at lower temperature (900°). Only the transport through the bulk was influenced by the microstructure, with the highest flux for the smallest grains. This would imply that oxygen transport occurs more rapidly along the grain boundaries that through the bulk. Grain and grain boundary compositions were analysed by TEM.