Corrosion behaviour of Ti-Nb-Sn shape memory alloys in different simulated body solutions

The corrosion resistance of Ti-Nb-Sn alloys in the 0.9% NaCl physiological and Hank's solutions with different pH values (2.4, 5.4, 7.4) at 37 ??C were investigated by means of open circuit potential (OCP), Tafel and anodic polarization techniques. The compositions of the passive films were analysed by X-ray photoelectron spectroscopy (XPS). The OCP was found to stabilize within several hours for Ti-Nb-Sn alloys in the Hank's solution but continued to increase in the 0.9% NaCl solution. Tafel results indicated that the corrosion current densities were in the magnitude of below 1 ??A/cm2. Anodic polarization curves demonstrated a wide passive region. XPS analysis results revealed that the passive film mainly consisted of TiO2, Nb2O5 and SnO2. These observations suggest that Ti-Nb-Sn alloys have a large potential for biomedical applications. ? 2006 Elsevier B.V. All rights reserved.EISPEC. ISS.891-895438-44