Passivity and corrosion behaviour of Ti-10Mo-4Zr and Ti-6Al-4V alloys after long-term ageing in Ringer's solution at 37 A degrees C

The influence of long-term ageing in the Ringer's solution at 37 A degrees C on the passivity and corrosion behaviour of Ti-10Mo-4Zr and Ti-6Al-4V is studied. XPS and AES results indicate that the chemical composition of the passive film formed on both alloys continuously changes with increasing ageing time. The passive film thickness increases, but a threshold value is reached at 780 and 1006 days of ageing. The current density in the passive range and in the cathodic branch of polarization curves drops after long-term ageing. In addition, the polarization resistance derived from impedance measurements increases by two orders of magnitude. These results show that the corrosion resistance of both alloys after long-term ageing is significantly improved.