Electrochemical behavior of Ti-Cr alloys in artificial saliva

In this study, the corrosion behavior of commercially pure titanium (c.p. Ti), Ti-6Al-4V and five new experimental Ti-Cr alloys was evaluated through open-circuit potential (OCP) and potentiodynamic polarization measurement in an artificial saliva containing fluoride. Electron spectroscopy for chemical analysis (ESCA) was used to characterize the composition of the passive films on the alloy after potentiodynamic polarization measurement. It was found that in standard artificial saliva the OCP increases with higher Cr content in Ti-Cr alloys. In 0.5% NaF artificial saliva, the OCP decreases with decreasing Cr in Ti-Cr alloys, and all but Ti-5Cr remain consistently higher than those of c.p Ti and Ti-6Al-4V. Linear polarization results show that artificial saliva and artificial saliva containing 0.5% NaF result in different corrosion behavior in Ti-Cr alloys, c.p.Ti and Ti-6Al-4V. The Ti-Cr alloys had greater resistance to corrosion in the fluoride-containing artificial saliva than c.p. Ti and Ti-6Al-4V, respectively. ESCA results verify that after potentiodynamic polarization a passive film consisting of TiO2 and Cr2O3 forms on the surface of Ti-Cr alloys. These experimental results show that the electrochemical corrosion behavior of Ti-Cr alloys in artificial saliva containing 0.5% NaF can be improved by increasing Cr content. This further indicates that Ti-Cr alloys could successfully be used for crown, bridge, and metal-ceramic restorations.