Typical microstructures of BaZr0.85Y0.15O3-delta sintered for 4-24 h at 1600 degrees C were mixtures of larger and smaller grains. Well-grown and homogeneous grains of BaZr0.85Y0.15O3-delta were observed by adding an extra amount of barium oxide from stoichiometric composition or extending the sintering time to 100 h. Such an extra amount of barium oxide is expected to decrease chemical stability in a wet atmosphere, and we observed the precipitation of yttria after 100 h sintering. However, we did not meet such difficulties in sintering BaZr0.85Sc0.15O3-delta. Large and uniform grains were observed in BaZr0.85Sc0.15O3-delta by sintering for 24 h. (C) 2007 The Electrochemical Society.