Effect of surface morphology on atmospheric corrosion behaviour of Fe-based metallic glass,Fe67Co18Si14B1

The nature of atmospheric corrosion behaviour of an as-cast metallic glass, Fe₆₇Co₁₈Si₁B₁₄ ribbon, was evaluated. The wheel side surface of the ribbon was more corroded than the air side surface, due to the higher density of air pockets present. The phases present in atmospheric rust were analysed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) to be goethite, lepidocrocite, magnetite, cobalt oxide and cobalt hydroxide phases. Goethite and lepidocrocite were in amorphous form. The nature of rusting was understood by scanning electron microscopy (SEM). Nucleation of rust started at preferred locations on the surface and grew along the surface in certain directions.