Release of elements from some gold alloys and amalgams in corrosion.

The release of Au, Ag, Cu and Zn elements from six commercially available gold alloys and three amalgam alloys was studied. The polarizing electropotential system with modified Fusayama solution was used. The cycle process was repeated 500 times between +/- 1000 mV during a period of 5 h 22 min. During the process samples of solution were analyzed in order to follow the release of elements. Results revealed rapid release of Zn from most alloys, release of Ag from most alloys and release of Au from two alloys. Also, rapid release of Cu was found from amalgams but not from gold alloys. Release of Ag from gold alloys showed very good passivation up to 3 h, after which it was released in varying amounts.