Ion release and tarnishing behavior of Au and Pd based amorphous alloys in artificial sweat

The corrosion resistance of Pd and Au based alloys in artificial sweat was studied using ICP-AES, XPS and SEM techniques. Amorphous ribbons were incubated for 1 week: the highest ion release was found for Au-based alloys, especially Au49Cu26.9Ag5.5Pd2.3Si16.3, while in Pd-based alloys it was one order of magnitude less. The Ni released from Pd32.5Cu7.5Ni40P20 was below the limit imposed by the European regulation for objects in contact with skin. Major surface modification was detected after incubation of Au49Cu26.9Ag5.5Pd2.3Si16.3, with formation of a nanoporous structure related to the observed tarnishing. Glassy alloys have higher corrosion resistance than the corresponding crystalline counterparts.