Nanorolls Decorated with Nanotubes as a Novel Type of Nanostructures: Fast Anodic Oxidation of Amorphous Fe-Cr-B Alloy in Hydrophobic Ionic Liquid.

The formation of oxide nanorolls decorated with nanotubes during anodic oxidation of amorphous Fe70Cr15B15 alloy in hydrophobic ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (IL) was revealed. The unusual architecture was observed for the first time on the surface of amorphous alloy. The generation of the novel type of nanostructure by electrochemical oxidation of the amorphous Fe70Cr15B15 alloy occurs only in hydrophobic ionic liquid and in the presence of the natural oxide film at the surface. Anodization of the oxide-free metal surface of the amorphous Fe70Cr15B15 alloy to be achieved by the treatment of the electrode with benzoic acid was found to result in no formation of both nanorolls and nanotubes. Electrochemical behavior of the amorphous Fe70Cr15B15 alloy in ionic liquid was proved to depend strongly on the state of the electrode surface before oxidation. The influence of the state of the surface of amorphous Fe70Cr15B15 alloy leading to the nanostructure formation was studied by means of preliminary partial etching with benzoic acid of various concentrations.