Enhanced corrosion and wear resistance via thermal oxidation treatment on Zr-2.5Nb alloy for implant applications

The Zr-2.5Nb alloys were selected for thermal treatment from 500 to 800 °C in air. The effects of oxidation temperature on microstructure, phase composition, oxide film thickness, hardness, and element distribution were investigated. The results revealed that the oxide film thickness and hardness showed a positive correlation as the oxidation temperature increased. The oxide film was mainly composed of ZrO2 and Nb2O5. The effect of oxidation temperature on the phase composition of the oxide film was also investigated, and it was found that the content of m-ZrO2 gradually increased with increasing temperature, and the content of Nb2O5 remained basically unchanged. Impedance and potentiodynamic polarization curves technique of oxide films in simulated body fluids at pH = 2.86 were investigated, and the results showed that a suitable thermal oxidation temperature could significantly improve the corrosion resistance of the Zr-2.5Nb alloy. In addition, the wear resistance of the specimens after thermal oxidation was investigated, and it was found that the wear resistance of the oxidized specimens was significantly improved. And the biocompatibility of the thermal oxide film was investigated by hemolysis test and contact angle experiments.