SrCo0.7Fe0.2Nb0.1O3-δ perovskite stabilized by niobium for oxygen permeation

The effect of Nb doping on the oxygen permeation and stability of SrCo0.8Fe0.2O3-δ(SCFO)was investigated comprehensively.Cubic perovskite phase was formed in SrCo0.7Fe0.2Nb0.1O3-δ(SCFNO).The SCFNO with a thickness of 1 mm had a high level of oxygen permeation flux of 1.4 ml·min-1·cm-2 at 850 ℃ under air/He gradient.The bulk diffusion is the rate-limiting step in overall oxygen permeation mechanism for SCFNO when the thickness is higher than 1.0 mm.The partial substitution of Nb for Co suppresses the transition of oxygen vacancies order/disorder proven by DSC measurement and enhances the phase stability under low oxygen partial pressure.During long-term tests under low oxygen pressure,the SCFNO extibites structural stability and stable oxygen permeation.It is proved that substitution of Nb for Co is an effective way to improve the properties of SCFO.