Electrochemical studies on the stability and corrosion resistance of new zirconium-based alloys for biomedical applications

The biocompatibility of commercially pure zirconium and its alloys is closely related to their surface properties with both the composition of the protecting oxide film and the surface topography playing an important role. This article is a study of corrosion behavior of new zirconium alloys for orthopedic implants, which are supposed to be used instead of some implant materials that have a higher citotoxicity. For this reason, zirconium and its alloys will be employed widely in biomedical applications. The higher stability and corrosion resistance exhibited by zirconium are due to the spontaneous formation of a passive zirconium oxide film, which protects the metal from further oxidation. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) are used as electrochemical techniques. Measurements were carried out to investigate the corrosion behavior of zirconium and Zr2.5Nb, Zr3Ta, and Zr2.5Nb3Ta alloys in aerated Hank solution at 37 +/- 0.2 degrees C. The results of EIS were compared with those obtained by potentiodynamic polarization techniques. impedance spectra were represented both in complex impedance diagram (Nyquist plot) and Bode plots. The EIS measurements have confirmed this stability range and pointed out the formation of oxide layers on the electrode surfaces. Copyright (c) 2008 John Wiley & Sons, Ltd.