Oxygen permeation and stability of La 0.6Sr 0.4Ti xFe 1− xO 3− δ ( x = 0.2 and 0.3) membrane

Abstract

An oxygen transport ceramic membrane was prepared with La 0.6Sr 0.4Ti x Fe 1− x O 3− δ ( x = 0.2 and 0.3) oxides which was synthesized by polymerized complex method. In order to investigate the effects of Ti substitutions into lanthanum–strontium ferrites, material property, thermal expansion coefficient, oxygen permeation, electrical conductivity and phase stability were examined according to Ti contents. The thermal expansion coefficients of LSTF6428 and LSTF6437 were 25.76 × 10 −6 K −1 and 21.32 × 10 −6 K −1 in the temperature range of 973−1273 K, respectively. The oxygen permeation fluxes through a disk type dense membrane of LSTF6428 and LSTF6437 with 1.6 mm thickness increased exponentially with increasing temperature and were 0.17 mL min −1cm –2 and 0.13 mL min −1cm −2 with P h = 0.21 atm (O 2 rich side) and P l = 10 −5 atm (lean side) at 1223 K, respectively. In the result of phase stability test with various conditions such as He, H 2/N 2 and CO 2 atmosphere, La 0.6Sr 0.4Ti x Fe 1− x O 3− δ was confirmed to be more stable than La 0.6Sr 0.4Ti 0.2Fe 0.8O 3− δ through XRD and SEM analysis.