OXYGEN IONIC TRANSPORT IN A-SITE-DEFICIENT PEROVSKITES LA(PB)FEO3

Formation of perovskite-type solid solutions were found in the oxide s ystem La1-xPbxFeO3-delta (x = 0.1-0.3). Synthesis and sintering of the ceramics at temperatures above 1300 K led to a cation deficiency in t he lanthanum sublattice, due to lead oxide evaporation. Electrical con ductivity and oxygen permeation fluxes were ascertained to increase wi th increasing x. Oxygen permeability values of the La1-xPbxFeO3-delta cation-deficient ceramics were considerably less than those of La1-xSr xFeO3-delta. Permeation fluxes through La1-xPbxFeO3-delta were demonst rated to be limited by the bulk ionic conductivity. Thermal expansion coefficients of the oxides were (10.0-10.4) x 10(-6) K-1. (C) 1998 Els evier Science Ltd.