METHOD FOR SYNTHESIZING COMPOUND OXIDE BY CITRATE METHOD

摘要

PURPOSE:To obtain an industrially mass-producible, high-performance and homogeneous compound oxide by reacting a coprecipitated substance or mixture of carbonates, basic carbonates, etc., of respective elements constituting a compound oxide with citric acid and calcining the resultant compound citrate. CONSTITUTION:A coprecipitated substance or mixture of respective elements constituting the above-mentioned compound oxide, i.e., Y and one or more elements selected from rare earth elements, transition metals and alkali (earth) metals is prepared. The resultant coprecipitated substance or mixture is then reacted with citric acid in an aqueous solution or organic solvent to afford a homogeneous fine particulate composite citrate, which is then dried at 50-120 deg.C, subsequently calcined at 800-900 deg.C and further sintered at 940-960 deg.C to provide a compound oxide. Furthermore, as for the afore-mentioned respective elements, La, Nd, etc., are respectively used as the rare earth elements and Cu, Ni, etc., are used as the transition metals. Na, Ba, etc., are used as the alkali (earth) metals. Furthermore, toxic gases, such as HNO3, NOx or CH3 COOH, are not emitted during calcining in the above-mentioned synthetic method as compared with a conventional method.