Evolución térmica de precursores de nitratos para el procesado de perovskitas de lantánidos

Abstract

Studies on thermal decomposition of ceramic powder with a general formula of (La 1-x Ba x ) (Co 0.8 Fe 0.2 )O 3 have been achieved. Precursors as nitrate solutions with additive of EDTA as complexion agent are used for powder processing. The black powders obtained are dried and their thermal evolution up to 1000¼C has been investigated by Differential Thermal Analysis. The powders was analyzed by EDX and ICP-AES, as well. It was established that the powder compositions are very close to the nominal one. The resulting DTA, TA, TG and DTG curves are analyzed as function of the composition and heating rate applied. At polythermal scanning regime three regions the powder thermal evolution are discussed. The correlation dependence has been examined for both Sr-and Ba-doped multicomponent lanthanide samples. The multicomponent nature of the samples have been shown on the base of the thermal treatment applied and XRD phase control carried out. Key words: thermal decomposition, lanthanum perovskites Evoluci-n tŽrmica de precursores de nitratos para el procesado de perovskitas de lant ‡nidosSe han realizado estudios sobre la descomposici-n tŽrmica de polvos cer ‡micos de f-rmula general (La 1-x Ba x ) (Co 0.8 Fe 0.2 )O 3 . Se utilizaron como precursores soluciones de nitratos con EDTA como agente acomplejante. La evoluci-n tŽrmica de el polvo negro obtenido se estudi-hasta la temperatura de 1000 ¼C por medio de an ‡lisis tŽrmico diferencial. Los polvos se analizaron as' mismo por EDX e ICP-A ES. Se estableci-que la composici-n de los polvos esta muy pr-xima a la composici-n nominal. Se distingue tres regimenes en la evoluci-n tŽrmica. Se examina la dependencia con el contenido en lantanidas multicomponentes de pulsos con Sr y Ba. La naturaleza multicomponente se ha mostrado sobre la base de el tratamiento tŽrmico empleado y el an ‡lisis de las fases cristalinas.Palabras clave: descomposici-n tŽrmica, perovskitas de lant ‡nidos.