Preparation and characterization of Ln(0.8)Sr(0.2)Fe(0.8)Co(0.2)O(3-x) (Ln= La, Pr, Nd, Sm, Eu, Gd)

In the present study the oxides Ln(0.8)Sr(0.2)Fe(0.8)Co(0.2)O(3-x) (Ln = La , Pr, Nd, Sm, Eu, Gd) were prepared and characterized to study the influenc e of the host rare earth cation on their properties and their potential app lication as intermediate temperature solid oxide fuel cell cathodes with hi gher ionic conductivity, lower linear thermal expansion coefficient and bet ter chemical compatibility with the electrolyte. The oxides were prepared b y the amorphous citrate synthesis. From X-ray powder diffraction measuremen ts it was deduced that all oxides were single-phased with the sensitivity o f the method. However, irregularities during thermal expansion measurements indicated that some structural changes might occur during heating. Only af ter examination of the powders in a scanning electron microscope, the prese nce of a second phase (cobalt oxide) in most compositions became evident. ( C) 2001 Elsevier Science Ltd.