Surface of precious dental alloys in artificial saliva observed by in situspecular reflection spectroscopy

In artificial saliva, the surface corrosion of precious dental alloys conta ining Au, Ag and Cu was studied by in situ specular reflection spectroscopy . The rest potentials of the alloys in contact with artificial saliva were about - 0.1 V similar to 0.1 V vs. SCE. It was found from the cyclic voltam mograms of the alloys, that AgCl and/or CuCl were formed on the alloy at mo re positive potential than 0.1 V. The formation of AgCl and/or CuCl was als o observed as a reflectivity-potential change using specular reflection spe ctroscopy. For an alloy containing a large amount of Au, Cl ion was adsorbe d on the alloy surface. Since the formation of AgCl and/or CuCl and the ads orption of Cl ion occurred at a more positive potential than the rest poten tial of alloy. It seemed that these alloys were stable in the artificial sa liva. To confirm the surface corrosion of the dental alloys, this in situ a nalytical method is thus sufficiently sensitive and useful.