Stability of oxide films formed on titanium and its alloys

The corrosion stability of the oxide films formed on titanium and two binary titanium alloys (Ti-15Mo, Ti-32Mo) surface in aggressive 20% and 60% nitric acid solutions at different temperatures was investigated. The influence of molybdenum on the behavior of the passive layers was distinguished. The study of these films was carried out using electrochemical impedance spectroscopy (EIS), potentiostatic and potentiodynamic polarization techniques. Titanium and its binary alloys are self-passivate in nitric acid solutions due to the forming of the protective, compact TiO2 oxide film. These passive films are more stable for the binary alloys than for the base metal, as a consequence of molybdenum's participation with insoluble oxides.