Abstract :
Amorphous Zr–Cu–Ni–Al–[Ti, Nb] ribbons prepared by melt spinning under argon atmosphere were subjected to
electrochemical investigations. Passive films developed at potentiostatic anodic polarization in sulphuric acid solution were
investigated by Auger electron spectroscopy (AES) and sputter depth profiling.
Changes in the shape of the Auger peaks have been analyzed by factor analysis of the spectra obtained during depth profiling.
Pronounced changes in shape and position occur for the Zr, Al, and Ti Auger transitions, but not for Cu and Ni. At least three
different peak shapes for O(KVV) were found and attributed to different oxygen binding states. The alloy composition has no
significant effect on the thickness and composition of the oxide layer.
In multi-element alloys preferential sputtering is a common phenomenon. In the steady state of sputtering, a significant
depletion in Cu is found. At the oxide/metal interface, a distinct enrichment of copper is found for all alloys and treatments. The
degree of this Cu enrichment depends on the pretreatment. It is higher for the electrochemically-passivated samples than for
samples with oxide layers grown during melt spinning.
