Oxygen ion irradiation effect on corrosion behavior of titanium in nitric acid medium

The corrosion assessment and surface layer properties after O5+ ion irradiation of commercially pure titanium (CP-Ti) has been studied in 11.5 N HNO3. CP-Ti specimen was irradiated at different fluences of 1 × 1013, 1 × 1014 and 1 × 1015 ions/cm2 below 313 K, using 116 MeV O5+ ions source. The corrosion resistance and surface layer were evaluated by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and glancing-angle X-ray diffraction (GXRD) methods. The potentiodynamic anodic polarization results of CP-Ti revealed that increased in ion fluence (1 × 1013–1 × 1015 ions/cm2) resulted in increased passive current density due to higher anodic dissolution. SEM micrographs and GXRD analysis corroborated these results showing irradiation damage after corrosion test and modified oxide layer by O5+ ion irradiation was observed. The EIS studies revealed that the stability and passive film resistance varied depending on the fluence of ion irradiation. The GXRD patterns of O5+ ion irradiated CP-Ti revealed the oxides formed are mostly TiO2, Ti2O3 and TiO. In this paper, the effects of O5+ ion irradiation on material integrity and corrosion behavior of CP-Ti in nitric acid are described.