Oxygen permeability of transition metal-containing La(Sr,Pr)Ga(Mg)O3-delta ceramic membranes

authors	Yaremchenko, AA; Shaula, AL; Kharton, VV; Kovalevsky, AV; Naumovich, EN; Frade, JR; Marques, FBM
nationality	International
journal	BOLETIN DE LA SOCIEDAD ESPANOLA DE CERAMICA Y VIDRIO
author keywords	ceramic membrane; mixed conductor; perovskite; lanthanum gallate; oxygen permeability
keywords	IONIC-CONDUCTIVITY; ELECTRONIC CONDUCTIVITY; DOPED LAGAO3; LACO(M)O-3 M; PEROVSKITES; TRANSPORT; FE; OXIDE; CR; NI
abstract	Acceptor-type doping of perovskite-type La1-xSrxGa0.80-yMgyM0.20O3-delta (x = 0-0.20, y = 0.15-0.20, M = Fe, Co, Ni) leads to significant enhancement of ionic conductivity and oxygen permeability due to increasing oxygen vacancy concentration. The increase in strontium and magnesium content is accompanied, however, with increasing role of surface exchange kinetics as permeation-limiting factor. At temperatures below 1223 K, the oxygen permeation fluxes through La(Sr)Ga(Mg,M)O3-delta membranes with thickness less than 1.5 mm are predominantly limited by the exchange rates at membrane surface. The oxygen transport in transition metal-containing La(Sr)Ga(Mg)O3-delta ceramics increase in the sequence Co < Fe < Ni. The ionic conduction in these phases is, however, lower than that in the parent compounds, La1-xSrxGa1-yMgyO3-n. The highest level of oxygen permeation, comparable to that of La(Sr)Fe(CO)O-3- and La2NiO4-based phases, is observed for La0.90Sr0.10Ga0.65Mg0.15Ni0.20O3-delta membranes. The average thermal expansion coefficients of La(Sr)Ga (Mg,M)O3-delta ceramics in air are in range (11.6-18.4) x 10(-6) K-1 at 373-1273 K. Doping of LaGa0.65Mg0.15Ni0.20O3-delta with praseodymium results in moderate increase of the permeation fluxes, lower thermal expansion and an improved phase stability in reducing environments.
publisher	SOCIEDAD ESPANOLA CERAMICA VIDRIO
issn	0366-3175
year published	2004
volume	43
issue	4
beginning page	769
ending page	774
web of science category	Materials Science, Ceramics
subject category	Materials Science
unique article identifier	WOS:000223052500010