Corrosion Stability of the Anodized Ultrafine-Grained Titanium in the Human Body Solution

Nanostructured surface modification was performed on the ultrafine-grained commercially pure titanium (UFG cpTi) using electrochemical anodization. The characterization of the morphology of the nanostructured surface obtained during different times of electrochemical anodization was done using scanning electron microscopy (SEM). The corrosion resistance of the materials was examined using the potentiodynamic method and electrochemical impedance spectroscopy (EIS), during which the electrochemical characteristics of oxide layers and the evaluation of the corrosion resistance of the mentioned materials were determined. These materials were exposed to a solution simulating conditions in the human body (artificial saliva solution) with a pH of 5.5 at a temperature of 37 ºC. The obtained results indicate the extensive influence of time, as a parameter of electrochemical anodization on the surface morphology. The electrochemical anodization of 60 minutes can lead to the creation of the nanotubular oxide layer on the UFG cpTi surface, while the electrochemical anodization of 30 and 90 minutes did not lead to the creation of the nanotubular oxide layer, but it is up to the surface modification of UFG cpTi. Electrochemical tests showed a slight increase in the corrosion resistance in a solution of artificial saliva after electrochemical anodization. Also, the electrochemical impedance spectra for anodized and non-anodized UFG cpTi show the characteristics of corrosion resistance, but the anodized UFG cpTi has better resistance to the oxide layer. It can be concluded that anodized UFG cpTi has better corrosion stability, but both non-anodized and anodized UFG cpTi show exceptional corrosion stability in simulated conditions of the human body, which makes them equally suitable for use in medicine.