The Effect of Mo and Al on the Corrosion Behavior of Titanium and Some of its Alloys for Biomedical Applications

The influence of molybdenum and aluminum on the corrosion resistance of the Ti and other Ti-based biomedical implant alloys under simulated physiological conditions is presented. Ti and its alloys Ti-10Mo and Ti-10Mo-10Al were studied. The electrochemical impedance spectroscopy technique was used and the experimental results were compared with those obtained by potentiostatic and potentiodynamic techniques. All the measurements were made in Ringer ́s solution at different pH and at different potentials as Ecorr, -650, -500, 0, +200 and +400 mV vs SCE. It was evident that Mo improved passivity and limited the active corrosion of the β-phase of Ti while Al enrichment of the α-phase was found to be detrimental to the passivity and corrosion resistance of Ti. In most experimental conditions, the passive film is formed by TiO2, Ti2O3 and TiO. When pH is very low, thermodynamically stable state of Ti is titanium anion Ti3+.