Oxygen ionic and electronic transport in LaGa1-xNixO3-δ perovskites

Formation of the LaGa1-xNixO3-delta solid solutions with perovskite structure was ascertained in the concentration range of 0 less than or equal to x less than or equal to 0.5, Substitution of gallium with nickel results in increasing oxygen nonstoichiometry and electronic and ionic conductivities. The oxygen ion transference numbers in air at 1070-1220 ii determined by the Faradaic efficiency measurements do not exceed 0.005. Oxygen permeation fluxes through LaGa1-xNixO3-delta were found to increase with nickel content and to be limited predominantly by the bulk ionic conductivity. Reducing oxygen partial pressure leads to decreasing electronic transport and increasing ionic conductivity, Thermal expansion coefficients of the ceramics are in the range of (10.8-11.6) x 10(-6) K-1. (C) 1999 Academic Press.