Electrochemical behavior of Ti-20Cr-X alloys in artificial saliva containing fluoride

摘要

In this study, electrochemical investigation was carried out on commercially pure titanium (c.p. Ti) and as-cast Ti-20Cr-X (X = Nb, Mo, Fe, and Cr) in fluoride solutions containing artificial saliva. Open-circuit potential (OCP) and potentiodynamic polarization measurement were used to characterize the electrochemical behavior, and X-ray photoelectron spectroscopy (XPS) was used to characterize the composition of the passive films on the samples. The OCP results indicated that all specimens presented spontaneous passivation. XPS results showed that pre-test, a passive film consisting of TiO_2 and Cr_2O_3 formed on the surface of the Ti-20Cr-X alloys, and Na_2TiF_6 formed on the surface of all specimens after the polarization test in artificial saliva with 0.5 wt% NaF. Although the Ti-20Cr-X alloys exhibited a Na_2TiF_6 film on their surface, their corrosion rate was still lower than that of c.p. Ti. In particular, Ti-20Cr-Mo alloy exhibited the lowest steady state current density compared to c.p. Ti and the other Ti-20Cr-X alloys. All these results suggest that the Ti-20Cr-X alloys hold promise for application as dental materials in a natural oral environment where NaF may be present.