Abstract
Our study investigates the influence of sintering temperature on the microstructure (grain size distribution, grain boundary length), electrical conductivity, and oxygen permeation properties of permeation membranes. For this purpose, SrSc0.1Co0.9O3-δ samples with different microstructures were prepared by varying the sintering temperature from 1100 to 1250 ˚C. The average grain sizes were gradually increased, thus the grain boundary lengths decreased with increased sintering temperatures. The influence of the ceramic microstructure on total electrical conductivity was found to be negligible. The oxygen transport properties of the samples were characterized by permeation measurements as a function of temperature in an air/helium oxygen partial pressure gradient. The decrease of the sintering temperature, meaning a decrease of grain size and thus the increase of grain boundary length, leads to an enhanced oxygen permeation flux and a reduced activation energy. This implies that oxygen exchange and transport in the SrSc0.1Co0.9O3-δ membranes occur more rapidly along grain boundaries than in the grain bulk.
Keywords:
Oxygen permeation membrane;; Perovskite; Grain size; Sintering temperatur; Strontium cobalt oxide
