Impact of Pretreatment of Metal Glass Fe70Cr15B15 on Anodization in 1-butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid

The impact of preliminary treatment (mechanical abrasion; chemical etching and anodization in ionic liquid) on the surface structure and corrosion behavior of Fe70Cr15B15 metal glass was studied. The detachment of the anodic oxide film from untreated Fe-amorphous alloy under anodization in ionic liquid was observed for the first time. The formation of hexagonal nanostructures (cells) on the surface of the Fe70Cr15B15 alloy after mechanical abrasion and following anodization in 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) ionic liquid was also detected for the first time. Electrochemical corrosion of the initial and pretreated amorphous alloy was tested in a Na2SO4 aqueous solution. The resistance to corrosion was found to be enhanced slightly after mechanical abrasion. The sample with hexagonal nanostructures obtained after anodization of the mechanically abraded sample demonstrated a more significant anodic shift in the corrosion potential (E-corr = + 379 mV) compared with that for the initial alloy (E-corr = -125 mV).