On the electrocontact oxidation of vacuum iron nanocondensates: II. Structural characteristics

Changes in the composition and morphology of thin-film conductors based on a nanostructured metal-oxide nanocomposite, which was obtained by the vacuum deposition of iron in an oxygen atmosphere at 10−5–10−3 mmHg on an amorphous glass substrate, induced by external electric current are studied using atomic force microscopy and Raman spectroscopy. The most pronounced zone of degradation is observed in the middle part of the conductor. Compared to the undistorted parts of the conductor, the degradation zone is characterized by an increased content of magnetite phase, which is formed as a result of the prevailing further oxidation of nanoparticles constituting the film. The surface morphology of the degraded part is characterized by the appearance of extended structures, some of which are nanoparticles and submicroparticles oriented in the direction of the applied electric current, which can be due to both the electric mass transfer of the metal and its electric oxidation. The other kind of extended structures are nanofibers composed of adjoining and coalesced metal-oxide nanoparticles, which can appear due to the electric oxidation in the electric contact areas between nanograins and leads to the coalescence of the neighboring nanograin chains into nanofibers. It is proposed that the electrocontact oxidation should be used as a method of creating fibrous metal-oxide nanocomposites based on vacuum deposits of iron or other metals.