Formation of iron oxide films from stabilized magnetite sols —magnetic liquids

Formation of thin supported iron oxide films from oleic acid stabilized Fe3O4 sols in decane medium has been studied using thermogravimetry, X-ray and electron diffraction, transmission electron microscopy, Mossbauer spectroscopy and chemical analysis. The continuous transparent films prepared by casting the sols over a flat substrate with subsequent heating in the air at 420–820 K were from 50–60 nm up to 1.5 μm thick, consisting of colloid-size particles. Intensive particle growth has been observed only above 670 K after complete removal of the dispersion medium and the stabilizer. The films had a crystal structure of magnetite on heating below 570 K, γ−Fe2O3 between 620 and 670 K and α−Fe2O3 above 670 K.