Preparation of La2-xSrxNiO4 (x=0-1.3) conducting oxides via a citrate route

La2-xSrxNiO4 (x = 0-1.3) oxide materials were prepared by the citrate and c eramic routes. The citrate precursors and final products were characterized by thermal analysis (DTA + TG), x-ray diffraction, scanning electron micro scopy, IR spectroscopy, and specific surface and conductivity measurements. The use of citrate mixtures leads to the formation of amorphous precursors to La2O3, NiO, and La2-xSrxNiO4 (x less than or equal to 0.4); reduces the temperature required for obtaining solid solutions by 150-200 degreesC as compared to the ceramic route; and enables the preparation of fine powders (less than or equal to5 mum) and dense ceramics.