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

Formation of thin supported iron oxide films from oleic acid stabilized Fe 3O 4 sols in decane medium has been studied using thermogravimetry, X-ray and electron diffraction, transmission electron microscopy, Mössbauer 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−Fe 2O 3 between 620 and 670 K and α−Fe 2O 3 above 670 K.