In this paper, nanosized SrCo0.4Fe0.5Zr0.1O3-delta (SCFZ) powders, which were synthesized via a flame aerosol synthesis (FAS) method, were successfully used to fabricate oxygen separation membranes with densified structure. XRD, TEM (HRTEM), O-2-TPD and TG were used to characterize the crystal structure, morphology, oxygen desorption property and oxygen non-stoichiometry of SCFZ-FAS powders. The densification process and the oxygen permeability of the SCFZ-FAS membranes were examined by SEM and the high temperature oxygen permeation measurements. The as-produced SCFZ-FAS powders were of the typical perovskite structure with high degree of crystallinity. Hard agglomerations, which were induced from the high temperature of the flame, were found among the nanosized rod-like SCFZ-FAS particles. Compared with SCFZ synthesized by the traditional solid-state reaction (SSR) method, the densification temperature of SCFZ membranes was reduced and the oxygen permeation flux was increased by 40% at the elevated temperatures (1073-1223 K) when SCFZ-FAS powders were used as the starting material. Long-term oxygen permeation measurement (1123 K, 180 h) showed that SCFZ-FAS possessed stable structure under low oxygen partial pressure (about 10(-3) atm) environment. (c) 2007 Elsevier B.V. All rights reserved.