Possible interactions between La0.9Sr0.1Ga0.8Mg0.2O2.85 and Gd2O3-doped CeO2 (solid electrolyte and anode binding materials, respectively, for solid oxide fuel cells (SOFC)) at 1300 degrees C were studied with diffusion couples and fired powder mixtures. The SrLaGa3O7 compound was detected and its formation was attributed to the diffusion of La2O3 from La0.9Sr0.1Ga0.8Mg0.2O2.85 into Ce1-xLaxO2-x/2 solid solution. As the resistivity of SrLaGa3O7 is rather high, around 1 M.ohm at 800 degrees C, its presence in the solid electrolyte/anode interface could significantly increase the internal resistivity of an SOFC. (C) 2000 Elsevier Science Ltd.