Passive and Semiconducting Properties Assessment of Passive Oxide Films Forming on Ti–6Al–4V Titanium Alloy in Ringer’s Physiological Solution at 37 °C: Role of Immersion Time and Anodic Passive Potential

The purpose of current study is to discuss the role of immersion time and passivation potential on the passive behavior and semiconducting properties of passive oxide films forming on Ti–6Al–4V titanium alloy in Ringer’s physiological solution at 37 °C. Polarization and impedance spectroscopy revealed that at longer immersion times and higher passivation potentials, Ti–6Al–4V shows a better passive response. Mott–Schottky (M–S) analysis revealed that the passive oxide films behaved as n-type semiconductor and immersion time and anodic passive potential did not affect the conductivity type of the passive oxide films. Moreover, M–S results indicated that fewer defects exist in the passive film at longer immersion times and higher anodic passive potential. The obtained results show that corrosion resistance of Ti–6Al–4V titanium alloy improves over the time and at higher passivation potentials due to the formation of passive films that are thicker yet less defective.