TY - JOUR
T1 - Influence of order-disorder transitions on oxygen permeability through selected nonstoichiometric perovskite-type oxides
AU - Kruidhof, H.
AU - Bouwmeester, H.J.M.
AU - van Doorn, R.H.E.
AU - Burggraaf, A.J.
PY - 1993
Y1 - 1993
N2 - New results on the oxygen permeability of perovskite-type oxides SrCo0.8B'0.2O3−σ (with B'=Cr, Fe, Co and Cu) and La0.6Sr0.4CoO3−δ are presented. The occurrence of order-disorder transitions at elevated temperatures (790–940°C) in these phases has been confirmed by DSC measurements and, in some cases, by X-ray powder diffraction of samples either slowly cooled or quenched from high temperature after annealing in different atmospheres. The oxygen permeability found upon exposing opposite sides of sealed disc specimens to a stream of air and of helium, respectively, increases sharply (between 5–6 orders of magnitude up to 0.3−3×10−7molcm−2s−1) at the onset of the transition from a low-temperature vacancy-ordered state to defec t perovskite, except for SrCo0.8Fe0.2O3−δ. In the latter case only a slight anomaly is found in the Arrhenius plot of th e oxygen permeability at ∼790°C. The comparatively high oxygen flux through SrCo0.8Fe0.2O3−δ observed at intermediate tempe ratures is interpreted in terms of a two-phase mixture of a vacancy-ordered state and disordered perovskite, while above ∼790°C the sample is single-phase of defect perovskite structure.
AB - New results on the oxygen permeability of perovskite-type oxides SrCo0.8B'0.2O3−σ (with B'=Cr, Fe, Co and Cu) and La0.6Sr0.4CoO3−δ are presented. The occurrence of order-disorder transitions at elevated temperatures (790–940°C) in these phases has been confirmed by DSC measurements and, in some cases, by X-ray powder diffraction of samples either slowly cooled or quenched from high temperature after annealing in different atmospheres. The oxygen permeability found upon exposing opposite sides of sealed disc specimens to a stream of air and of helium, respectively, increases sharply (between 5–6 orders of magnitude up to 0.3−3×10−7molcm−2s−1) at the onset of the transition from a low-temperature vacancy-ordered state to defec t perovskite, except for SrCo0.8Fe0.2O3−δ. In the latter case only a slight anomaly is found in the Arrhenius plot of th e oxygen permeability at ∼790°C. The comparatively high oxygen flux through SrCo0.8Fe0.2O3−δ observed at intermediate tempe ratures is interpreted in terms of a two-phase mixture of a vacancy-ordered state and disordered perovskite, while above ∼790°C the sample is single-phase of defect perovskite structure.
U2 - 10.1016/0167-2738(93)90202-E
DO - 10.1016/0167-2738(93)90202-E
M3 - Article
VL - 63-65
SP - 816
EP - 822
JO - Solid state ionics
JF - Solid state ionics
SN - 0167-2738
ER -