TA10 Titanium Alloy in HCl Solution: W‐Influenced Corrosion and Passivation Film Evolution

ABSTRACT

This work investigated the evolution of passive films of Ti–0.3Mo–0.8Ni (TMN) in 5 mol L ⁻¹ HCl and studied the influence of W on the anti‐corrosion properties of TMN. The intermittent electrochemical impedance spectroscopy test results showed that when TMN entered 5 mol L ⁻¹ HCl solution, the stability of the passive film first became stronger and then became weaker. Finally, the passive film was completely destroyed. We proved that the dynamic change process of the passive film has a strong correlation with the slope of an open circuit potential (OCP) curve by the first derivative of the OCP curve. W reduces the content of high valence metal oxides such as TiO ₂ and WO ₃ in the passive film, whereas the content of low valence metal oxides such as Ti ₂ O ₃ , TiO, and metallic Ti and W increases. W also reduces the content of O ²⁻ , whereas that of OH ⁻ increases, and WO ₃ is introduced into the passive film. W reduces the stability of the passive film by changing its composition. Although atomic force microscopy characterization and first‐principles calculation results showed that W atoms increase the work function between the β phase and α phase, which aggravates the interphase galvanic corrosion of α/β, W atoms also reduce the density of states near the Fermi level of the α phase and β phase and increase the phase content of the β phase in the alloy. Under the combined effect of the above factors, the W element improves the corrosion resistance of the TMN alloy.