Corrosion behaviors of TiO2 nanotube layers on titanium in Hank's solution.

It is well known that the growth of osteoblast cultured on titanium with nanotube layers can be significantly increased compared to unanodized surfaces. In the current study, the corrosion behavior of titanium with nanotube layers was studied in naturally aerated Hank's solution using open circuit potentials (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. The electrochemical results indicated that TiO2 nanotube layers on titanium showed a better corrosion resistance in simulated biofluid than that of smooth-Ti. The OCP, corrosion rate (I(corr)), passive current density (I(pass)) and the oxygen evolution potential (E(o)) were significantly influenced by titanium oxide nanotube layers acquired by anodization. The anatase nanotube layer showed higher OCP and smaller current density than the amorphous nanotube layer. EIS analysis showed that the annealing had a significant effect on the corrosion resistance of the outer tube layer (R(t)), but little effect on the corrosion resistance of the inter-barrier layer (R(b)) for nanotube layers. The results suggested that titanium with TiO2 nanotube layers has an adequate electrochemical behavior for use as a dental implant material.