Synthesis and Investigations of Morphology and Structure of Fe₂O₃ Nanocoatings on Porous Al₂O₃, Obtained by Oxidation of Magnetron Deposited Fe Films

The results of studies of the morphology, crystal, local atomic and chemical structure of iron(III) oxide coatings on the surface of porous alumina with different morphology by scanning electron and atomic force microscopy, X-ray phase analysis, X-ray photoelectron spectroscopy, as well as fine structure spectroscopy of the near edge region are presented. X-ray absorption. Films of porous alumina were synthesized by the method of two-stage anodic oxidation of aluminum in aqueous 0.3 M solutions of sulfuric and oxalic acids. To change the pore diameter, some of the films were etched in a phosphoric acid solution. Samples of iron oxide nanocoatings were obtained by air oxidation of iron films deposited on porous alumina substrate matrices by magnetron sputtering at a temperature of 300°C for 3 hours. It is shown that oxidation leads to a twofold increase in the coating thickness of the control sample and is associated with an increase in the density of iron oxide compared to pure iron. With a change in the nanoporous structure on the surface of the substrates, the morphological features of the coatings change, which consists in the “overgrowth” of pores with iron oxide. That the control of the processes leading to such “overgrowth” will make it possible to carry out a directed change in the structure-sensitive properties of composite structures based on iron oxide.