Photoemission study of ternary to penternary Fe-based metallic glasses: Chemical analysis of surface and bulk

Bulk metallic glasses consisting of Fe, Mo, Cr, C, B, and Er have been investigated by x-ray photoelectron spectroscopy, aimed to elucidate the local atomic structure of the amorphous phase. In order to examine the electronic properties of this class of material, photon energy dependent measurements in combination with argon-ion irradiation were employed to identify and separate surface and bulk contributions to the spectra. The core levels suggest the presence of a carbon-rich surface layer with oxidized boron and metals, and metal carbides and borides in the bulk. Exposure to molecular oxygen and annealing experiments probe the chemical reactivity of the material. Formation of boron oxides at comparably low temperatures (300 deg. C) might have consequences for the stability of the amorphous phase. We observe variations in binding energy of the Fe 3p core level with respect to the alloy composition, which indicate changes in the chemical state of iron