Corrosion behavior of Ti-Nb-Ta-Zr-Fe alloy for biomedical applications in Ringer’s solution
(1. School of Mechanical Engineering, Xiangtan University, Xiangtan 411105, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China)
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The corrosion resistance of Ti-25Nb-10Ta-1Zr-0.2Fe (mass fraction, %) (TNTZF) alloy in Ringer’s solution at 37 °C was investigated by potentiodynamic polarization measurement. Ti-6Al-4V ELI (Extra low interstitial) alloy was also investigated to make a comparison. The results show that TNTZF alloy has higher corrosion potential, lower corrosion current density, more stable passive current density and wider passive region compared with Ti–6Al–4V ELI alloy, which indicates that TNTZF alloy has better corrosion resistance. In addition, pitting corrosion is observed on the surface passive film of Ti–6Al–4V ELI alloy but is not found on that of TNTZF alloy. The XPS analysis results reveal that the passive film formed on TNTZF alloy is composed of Nb2O5, NbO2, Ta2O5, ZrO2, TiO and Ti2O3 oxides in the matrix of TiO2, which makes the passive film more stable and protective than that formed on Ti-6Al-4V ELI alloy and contributes much to its superior corrosion resistance.
Key words: Ti alloy; biomaterials; corrosion behavior; passive film