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

Abstract

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.