Structural Analysis, Tribological and Hardness of Titanium Grade 2 Anodized, Using HCI and Ethylene Glycol as Electrolytic Solution

Abstract

One of the main difficulties present in the materials manufacturing is the selection of substances that generate less polluting residues as well as effective in the synthesis process. In this study, we obtained TiO2 through electrochemical anodizing, using an acid easy to neutralize (hydrochloric acid), ethylene glycol and distilled water. The results showed the presence of nanostructures over the anodized surface observed by Scanning Electron Microscopy, with anatase and rutile phases, identified with Raman Spectroscopy. The presence of a nanostructured material on the surface of titanium, improved the value of Vickers Micro-hardness from 240 HV to 400 HV. It was possible to obtain a reduction of the friction coefficient from 0.8 to 0.2 as minimum value. The presence of a nanostructured layer of TiO2, with a mixture of anatase and rutile, markedly improved the mechanical properties of the titanium sheet.

Morphological and Structural Study of Anodized Titanium Grade 2, Using HCl in Aqueous Solution

“…The formation of nanostructures on the surface of anodized titanium was observed at a concentration of 3M at 11V in 10 min, which can be seen in Figure 2 with magnifications of 30,000 and 50,000 x. It can be seen that the anodized surface showed a certain degree of homogeneity in the growth of nanopores, this behavior is similar to that reported in the literature where they also use HCl as an electrolyte solution 12 . Subsequently, the dimensions of the nanostructures were measured using ImageJ software.…”

“…According to the materials used for the anodizing process, it is possible to classify the electrolyte solutions into four generations that are correlated for the study of titanium anodization 5,6 . For this particular study, the fourth generation was considered, in which the presence of chloride ions during the anodizing process helps the formation of nanostructures over the outside of the material, in particular, nanopores and TiO 2 nanotubes [7][8][9][10][11][12][13][14] .…”

“…It has been reported that the use of electrolytes with Fions can generate safety problems, toxicity or other concerns for industrial scale applications, and ways have been sought to improve the anodizing method by using non-precious metal electrodes and environmentally benign electrolytes for the preparation of TiO 2 nanotube films 7 . The anodized materials are characterized by the formation of nanostructures on the oxide layer, which can obtain several properties such as the increase in their hardness values, improvement of their tribological properties 12,15 and also be used for photocatalytic and biological applications, sensors, photoelectrochemical hydrogen generation and solar cells [7][8][9][10][11][13][14][15] . The formation of TiO 2 nanostructures are generated by a series of steps during the anodizing process.…”

“…For the first step of formation of nanostructures on the surface of titanium, an oxidation process occurs due to the presence of dissolved OHions, the titanium is ionized with a positive charge that attracts these ions and generates the growth of a layer of negative ions, likewise, Clions are also involved in this process. Subsequently, the saturation of negative materials leads to a reversal of the charge, and due to the growth of the non-conductive TiO 2 layer, the second stage begins with the dissolution of the negative ions involved by means of the reaction with the positive H + and/ or H 3 O + ions, thus generating the formation of possible pores on the oxidized surface 12 . In this study, the electrochemical anodization technique was used to obtain TiO 2 nanostructures from HCl as electrolyte solution, varying the voltage and anodization time, at different concentrations, at 0.15 and 3 M, at room temperature, since there is very little reported in the literature the analysis of morphology, microstructure and optical properties of titanium grade 2 anodized with electrolytes based on chloride ions.…”

Study of the Variation of the Voltage and Time of the Process in the Anodizing of TiO2 with HCl

“…The study of TiO2 nanostructures obtained by a chlorine-based substance has generally focused on observing morphology (6)(7)(8)(9), structural composition (4,(10)(11)(12)(13)(14) reflectance and optical analysis (15,16). Studies have recently been conducted on the mechanical and tribological properties of HCl anodized TiO2 (17,18), where it is observed how the nanostructured oxide layer is capable to award a significant improvement in the values of hardness and the coefficient of friction compared to those corresponding to titanium. Therefore, in this work, an analysis of the hardness and the coefficient of friction of samples anodized with HCl, ethylene glycol and deionized water was carried out, considering a variation in voltage and an increase in process time as the factors of greatest interest for the study.…”