Electrochemical Studies on the Stability and Corrosion Resistance of Ti-6Al-4V Alloy for Biomedical Applications
Résumé
Titanium and titanium-based alloys are widely used in various biomedical applications. This is due to the stability and corrosion resistance exhibited by titanium, which in turn related to the spontaneous formation of a passive oxide film, typically with a thickness of a few nanometers, which protects the metal from further oxidation. By means of Surface Mechanical Attrition Treatment (SMAT), a nanostructured surface layer was formed on a Ti-6Al-4V alloy. Microstructure features of various sections in the surface layer, from the strain-free matrix to the treated top surf ace, were systematically investigated by using Optical microscope (OM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) observations. Corrosion resistance of Ti-6Al-4V in a Ringer's solution was studied by potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) measurements. Overall results of all studies identified beneficial impacts of SMAT on corrosion behaviour of Ti6Al4V. The surface oxide film formed on Ti-6Al-4V and its stability in biological environments play a decisive role for the biocompatibility of implants. In this study, passive oxide films formed on Ti6Al4V surfaces and their natural growth in a Ringer's solution have been investigated by Scanning Electron Microscopy (SEM), microhardness and X-ray Photoelectron Spectroscopy (XPS).