XPS study of gold-based metallic glass

New multinary amorphous materials, based on gold, that can be produced in bulk form due to their high glass-forming tendency, were discovered recently. However little is known about their corrosion properties. In the present study, the characterization of Au49Cu26.9Ag5.5Pd2.3Si16.3 amorphous ribbons produced by melt spinning is reported. Their corrosion properties were tested by incubating the samples in artificial sweat and bymonitoring the changes in surface structure by SEM and XRD. Before incubation, the surface of the sampleswas amorphous and flat, characterized only by microfeatures due to the liquid contact with the wheel during quenching. After treatment with artificial sweat, the formation of nanosized crystallites of Au on the sample surface was observed. The surface chemical composition of both sides of the ribbon samples was investigated by XPS. Atomic concentration and chemical states of constituent elements before and after the incubation in artificial sweat were determined. The depth profiling of both sides of the sampleswas carried outby using Ar ion sputtering combined with cyclic XPSmeasurements. The segregation of Si on one side of the samples and the changes of chemical composition, caused by the treatment in artificial sweat, were revealed. Copyright (C) 2010 John Wiley & Sons, Ltd.