Effect of Zr addition on the corrosion resistance of Ti-Mo alloy in the H2O2-containing inflammatory environment

• The corrosion behavior of Ti-12Mo and Ti-12Mo-5Zr was verified in PBS + H 2 O 2 . • Ti-12Mo-5Zr had enhanced corrosion resistance at OCP and under cathodic potential. • The mechanism of Zr-induced corrosion enhancement depends on electrochemical conditions. • At OCP Zr suppress oxide film growth in PBS + H 2 O 2 . • At cathodic potential Zr suppresses Ti dissolution in PBS + H 2 O 2 . Reactive oxygen species (ROS), produced by immune cells during inflammatory reaction, are known to promote corrosion of standard biomedical materials such as CP-Ti and Ti-6Al-4V. Electrochemical corrosion in the ROS environment can be further accelerated in the vicinity of fretting regions, where titanium can be polarized towards negative potentials. This study considers both of these aspects and presents corrosion analysis under complex inflammatory conditions for Ti-Mo and Ti-Mo-Zr alloys, which offer exceptional strain-hardening behavior and ductility. Combining electrochemical impedance spectroscopy (EIS) and atomic emission spectroelectrochemistry (AESEC) allowed us to understand the origin of ROS-induced corrosion. At free corrosion conditions, Zr was found to suppress oxide layer growth without any significant effect on the dissolution process. On the other hand, Zr suppressed dissolution rate under cathodic potentials. Although applying cathodic potential resulted in a rapid increase of dissolution rate, cross-section transmission electron microscopy (TEM) analysis did not reveal significant influence of the short cathodic polarization on the oxide film growth during further prolonged exposure at free corrosion conditions.