Electrochemical aspects of Ti-Ta alloys in HBSS

摘要

Corrosion behaviour of the studied Ti-Ta alloys with Ta contents of 30, 40 and 50wt% together with the currently used metallic biomaterials commercial pure titanium (Cp-Ti) was investigated for biomedical applications. All the samples were tested by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in Hank's balanced salt solution (HBSS) with and without albumin protein at 25℃. Very low corrosion current densities and passive current densities (in the order of 10~(-6) A/cm~2) were obtained from the polarization curves, indicating a typical passive behaviour for all the samples in HBSS with and without albumin. The EIS technique was applied to study the nature of the passive film formed on all the samples at various imposed potentials -500mV (SCE), 0mV (SCE), 500mV (SCE) and 1000mV (SCE). The equivalent circuit (EC) used successfully to describe the behaviour of the samples suggests a single passive film present on the metals' surface in HBSS with and without albumin. The results showed that the presence of albumin in HBSS had an influence on the zero current potential (ZCP), polarization resistance (R_p) and capacitance (C). The presence of albumin protein in HBSS improved slightly the corrosion resistance of the entire sample. The experimental results confirm that the electrochemical behaviour of the studied Ti-Ta alloys is better to that of Cp-Ti, suggesting their promising potential for biomedical applications.