Effect on thermal oxidation in TiO2 nanostructures on nanohardness and corrosion resistance

Abstract

This article aimed to analyze the effect of the thermal oxidation in the corrosion resistance and the hardness properties of TiO 2 nanostructures obtained by the anodizing process in the HF/H 3 PO 4 solution . TiO 2 nanostructures on Ti6Al4V obtained by anodizing processes were subjected to thermal oxidation (TO) treatments over a temperature range from 500 ºC to 620 ºC for 2 hours. Surface morphology was evaluated by using scanning electron microscopy; the hardness properties of TiO 2 nanostructures were obtained by Nanoindentation measurements using a Berkovich probe with a tip radius of 150 mm. The corrosion behavior of the samples was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that TiO 2 nanostructures, modified by thermal oxidation, increased the surface properties of hardness and corrosion resistance, compared to the substrate, maintaining its mixed or tubular structure. On the other hand, a transformation of nanotubes to nanopores after 600ºC was evidenced, generating significant changes in the mechanical properties of these structures.

Electrochemical Anodic Synthesis and Analysis of TiO2 Nanotubes for Biomedical Applications

“…Table 1 represents the 3 Journal of Nanomaterials E corr and i corr values that were changed due to the passivation layer thickness increment. The polarization curves start from the active region (-0.5 mV) to the passive region (+ 4 mV), which is the standard measurement method of this type of sample [21]. The cathodic reaction is nothing but the gain of electrons from the environment to the material.…”

“…This change of frequency may be the rib formation all over the nanotubes at the high-frequency results. An increase in frequency level can also be due to the absorption by nanotubes; ingredients present in the SBF solution take a high electrical resistance [21].…”