Structure of SrCo0.5Fe0.5O3-δ-based composites prepared by sol-gel and mechanochemical processes

X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Mossbauer spectroscopy have been used to investigate the structural phase transformations of SrCo0.5Fe0.5O3 - delta-based mixed-oxide nanocomposites containing fine iron oxide particles. The nanocomposites have been prepared using sol-gel and mechanochemical processes. The addition of iron(III) oxide sol to SrCo0.5Fe0.5O3 - delta xerogel is shown to enhance the thermal stability of the resultant cubic perovskite phase. The stabilization is due to partial shielding of the perovskite surface with a thin Fe2O3 layer, which hinders cobalt diffusion to the surface, preventing Co3O4 formation.