The O-ion transport in dense LaGa0.65Ni0.20Mg0.15O3-δ membranes, prepared by using a standard ceramic synthesis technique or the glycine-nitrate process, was studied via measurements of the total conductivity, O permeation and Faradaic efficiency. At 1223K, O transfer through LaGa0.65Ni0.20Mg0.15O3-δ ceramics was governed mainly by the bulk ambipolar conductivity, while a decreasing temperature led to a greater role for the surface exchange rate. In spite of moderate difference in the ceramic microstructures, the surface exchange limitations were considerably higher for the membranes prepared by using the standard ceramic route as compared to glycine-nitrate-synthesized material. Thermal expansion and partial ionic and electronic conductivities were found to be essentially independent of the synthesis method. The level of O ionic conduction in LaGa0.65Ni0.20Mg0.15O3-δ, characterized by an activation energy of about 150kJ/mol and ion transference numbers in the range of 10-3 to 5 x 10-2 at 973 to 1223K, was higher than that in La(Ga,Ni)O3-δ perovskites and was comparable to that in La2NiO4-based phases.

Oxygen Permeability of LaGa0.65Ni0.20Mg0.15O3-δ Ceramics - Effect of Synthesis Method. A.L.Shaula, A.P.Viskup, V.V.Kharton, D.I.Logvinovich, E.N.Naumovich, J.R.Frade, F.M.B.Marques: Materials Research Bulletin, 2003, 38[2], 353-62