Corrosion behavior of self-organized TiO2 nanotubular arrays grown on Ti6Al4V for biomedical applications

Abstract

The electrochemical interactions between a biomaterial and a human fluid are important to understand when developing surfaces on titanium biomedical composites to improve bone regeneration, healing times, and longevity. Electrochemical corrosion is a major problem in implant-tissue interaction in that environment. The purpose of this research is to use different electrochemical methods such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) to examine the effect of self-organized TiO2 nanotubular surfaces on the corrosion resistance of Ti6Al4V surface. The electrochemical behavior of polished Ti6Al4V (control), and anodized samples at a constant voltage of 30V and various time-periods of anodization, such as 3hr, 4hr, and 5hrs respectively is the main focus of our study. All the anodized samples were annealed at 500 °C for 3hr with preheating rate of 5 °C per minute. The resistance of the nanotubular structure is improved after annealing because the anatase phase is stabilised, and the fluoride ions are removed. The electrochemical behavior of the nanotubular surfaces were investigated by using the simulated body fluid (SBF, 7.4 pH) solution. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and a Drop Shape Analyzer were all used to investigate the nanotubular morphology, chemical compositions, and structure. According to the findings, the anodic oxidation process results in a nanotubular structure that improves the surface area and influences the surface's chemical composition. Surfaces with self-organized TiO2 nanotubular structures had greater corrosion resistance than polished Ti6Al4V because the passive film had a larger surface area and a more dispersed amorphous crystal structure. Finally, the physical condition of the post-electrochemical treated sample was evaluated by the SEM images and compositional analysis by the EDS and XRD. The PDP curves showed the corrosion rate of the samples polished Ti6Al4V, TiO2 30V 3hr, TiO2 30V 4hr, and TiO2 30V 5hrs are 0.39, 0.35, 0.09, and 0.24 mm per year respectively. Similarly, the efficiencies of the anodized samples TiO2 30V 3hr, 4hr, and 5hrs are 9.96, 76.44, and 38.30% respectively. When comparing all of the anodized samples, the overall corrosion resistance is improved by 2 times.