Tribological, electrochemical and tribo-electrochemical characterization of bare and nitrided Ti6Al4V in simulated body fluid solution

Tribological, electrochemical and tribo-electrochemical behaviour of bare and nitrided Ti6Al4V alloy was studied. Scanning Electron Microscopy (SEM), X-ray diffraction and microhardness profile were used to characterize the nitrided Ti6Al4V. The anticorrosive properties of nitrided Ti6Al4V in phosphate buffer saline solution (PBS), simulating the body environment, were evaluated by Electrochemical Impedance Spectroscopy (EIS). Nitriding increased the alloy resistance to corrosion and to dry wear. Resistance to tribocorrosion in PBS at the open circuit potential (OCP) for the nitrided alloy was also significantly increased compared to the bare alloy; nevertheless at an anodic potential this influence became less important.

Research highlights
► Tribocorrosion of bare and nitrided Ti6Al4V in simulated body fluid is studied.
► The alloy presents great tendency to repassivate when its oxide is damaged by wear.
► Nitriding increases Ti6Al4V resistance to wear-corrosion at open circuit potential.
► EIS results confirm the improved anticorrosion properties of the nitride layer.
► Anodic potentials (+0.4VSCE) impair tribocorrosion resistance of the alloy.