Effect of Ag on the corrosion behavior of Ti-Ag alloys in artificial saliva solutions.

The purpose of this study was to investigate the corrosion behavior of Ti-Ag alloys in artificial saliva solutions. The corrosion behavior of experimental Ti-Ag alloys in artificial saliva was examined by means of potentiodynamic polarization measurements. The surface passive film formed was analyzed by means of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) methods. The alloys were found to develop surface passive films after immersion for 1.8 x 10(3)s. In comparison with commercially pure Ti, the Ti-Ag alloys exhibited better corrosion resistance with lower anodic current densities, larger polarization resistances, and higher open-circuit potentials. The passive film formed was predominantly composed of TiO(2), as determined by XPS. When fluoride ions were added in the solution, the TiO(2) passive film was destroyed and Na(2)TiF(6) was formed. Addition of Ag was found to be effective in reducing the corrosion current density and increasing the open circuit potential of titanium in artificial saliva environment. Addition of fluoride ions in the solution severely reduced the corrosion resistance of Ti-Ag alloys.