بررسي پايداري ساختاري و خواص عبوردهي اكسيژن از غشاء پروسكايتي Ba0.5 Sr0.5 Co0.8 Fe0.2 O3-(delta)

An Investigation on Structural Stability and Oxygen Permeation Properties of Dense Membrane Perovskite Ba0 5Sr0. 5Co0.8Fe0.203-5

In this study, perovskite Ba0.5Sr0.5Co0.8Fe0.2O3_6 and SrCo0.8Fe0.2O3_5 were synthesized by EDTA and citrate complexing methods. The microstructural studies were carried out using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to investigate the crystal structure and also structural stability. Oxygen permeation through BSCF and SCF membranes were measured at elevated temperatures (700°C to 950°C). XRD results showed that both specimens possess perovskite and cubic structure. A relatively high permeation value (2 cc/min.cm2 at 950°C) were reported for both specimens. The results indicated that oxygen permeation of BSCF is higher than that of SCF through a wide range of temperature. Also, the effect of upstream partial pressure of oxygen (0-1 atm) on oxygen flux was studied at various temperatures. The increase in oxygen partial pressure significantly increases the oxygen flux which suggests that these membranes may be used for industrial application. Activation energy results revealed that permeation of SCF membrane at low temperatures is more sensitive to temperature than BSCF which is contrary to observations at high temperatures. It was concluded that Oxygen permeation flux is controlled by both surface exchange kinetics and bulk diffusion. XRD patterns after (adsorption-desorption treatment) indicated that BSCF has a more stable structure at high-temperatures than SCF and also possesses lower oxygen partial pressures.