Oxygen permeability and thermal expansion of SrCo(Ti)O3-δ perovskites

Formation of the solid solutions with the cubic perovskite-type structure has been found in the SrCo1-xTixO3-delta oxide system at 0.05 less than or equal to x less than or equal to 0.20. The substitution of cobalt with titanium leads to increase in thermal expansion as well as electrical conductivity. The conductivity of the SrCo(Ti)O3-delta solid solutions has been shown to decrease regularly with reducing oxygen partial pressure. The mean values of thermal expansion coefficient calculated from the dilatometric data for the SrCo1-xTixTixO3-delta ceramics are (13-18) x 10(-6) K-1 the temperature range 300-700 K and (25-29) x 10(-6) K-1 at 800-1100 K. The introduction of titanium into the cobalt sublattice results in increasing oxygen permeation flux through the strontium cobaltite ceramics owing to decreasing oxygen non-stoichiometry and stabilization of the cubic perovskite phase. The oxygen permeability values of SrCo1-xTixO3-delta at x=0.05-0.20 are close to each other. (C) 1998 Elsevier Science S.A.