Corrosion behavior of biomedical Ti–24Nb–4Zr–8Sn alloy in different simulated body solutions

Corrosion behavior of a multifunctional biomedical titanium alloy Ti–24Nb–4Zr–8Sn (wt.%) in 0.9% NaCl, Hank's solution and artificial saliva at 37 °C was investigated using open circuit potential, impedance spectroscopy and potentiodynamic polarization techniques, and some results were compared with pure titanium and Ti–6Al–4V alloy. The results showed that the alloy exhibited good corrosion resistance due to the formation of a protective passive film consisting mainly of TiO2 and Nb2O5, and a little of ZrO2 and SnO2. Ca ions were detected in the passive film as the alloy immersed in Hank′s and artificial saliva solutions and they have negative effect on corrosion resistance. The EIS results indicated that either a duplex film with an inner barrier layer and an outer porous layer or a single passive layer was formed on the surface, and they all transformed into stable bilayer structure as the immersion time increased up to 24 h. The polarization curves demonstrated that the alloy had a wider passive region than pure titanium and Ti–6Al–4V alloy and its corrosion current density (less than 0.1 μA/cm2) is comparable to that of pure titanium.

► Corrosion behavior of a multifunctional Ti2448 bio–Ti alloy was investigated.
► The passive film consists mainly of TiO2 and Nb2O5 and a little of ZrO2 and SnO2.
► The alloy displays a wider passive region than pure titanium and Ti–6Al–4V alloy.
► Its corrosion current density is comparable to that of pure titanium.
► Ca ions in the passive film reduce its corrosion resistance.