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

Formation of the LaGa1-xNixO3-delta solid solutions with perovskite structu re 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 i ncreasing oxygen nonstoichiometry and electronic and ionic conductivities. The oxygen ion transference numbers in air at 1070-1220 ii determined by th e Faradaic efficiency measurements do not exceed 0.005. Oxygen permeation f luxes through LaGa1-xNixO3-delta were found to increase with nickel content and to be limited predominantly by the bulk ionic conductivity. Reducing o xygen partial pressure leads to decreasing electronic transport and increas ing 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.