Oxide formation on the bulk metallic glass Zr46.75Ti8.25Cu7.5Ni10Be27.5

In this investigation depth profiling by Ar(+) ion sputtering in combination with x-ray photoelectron spectroscopy was used to determine the thickness and the chemical composition of the oxide layers formed on the bulk metallic glass Zr(46.75)Ti(8.25)CU(7.5)Ni(10)Be(27.5) (V4) under different preparation conditions. The thickness of the oxide layer was in the range between 4 nm and 30 nm for samples oxidized in air at room temperature and annealed in air at 573 K for 15 hours, respectively. The oxide layers showed an enrichment of Be at the outermost surface followed by a Be, Zr and Ti rich phase. Cu and Ni are depleted within the whole oxide layer. BeO, ZrO(2) and various Ti oxides were detected in the oxide layer, whereas Cu and Ni occurred only in a non-oxidized zerovalent state. Our data indicate that the oxidation is controlled by the inward and outward diffusion of the metallic components.