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.

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In the present study an electrochemical adonization procedure was used to manufacture the nanostructures, to improve the hardness and to reduce long term damage on the Ti-6Al-4V alloy, using a glycerol organic tool and HCl as an electrolyte. With Raman microscopy, different vibrational modes related to the two TiO2 phases (anatase and rutile) were observed. Using scanning electron microscopy, a uniform growth of TiO2 nanotubes was observed when the percentage of glycerol was increased in the solution. The hardness value raised 6.75 GPa, but after anodization and thermal treatment a maximum value of 10.25 GPa was achieved, according to the value reported of the alloy that is between 2.942 GPa and 3.92 GPa. Finally, the TiO2 nanostructures growing process made a hardness improvement and lowered the alloy friction coefficient from 0.67 to a minimum of 0.59.

The paper presents results of synthesis and characterization of TiO2 thin films doped with low percentages of tungsten using the magnetron co-sputtering technique. The influence of tungsten concentration on the structure, hardness and electrical resistivity was analyzed using different characterization techniques such as X-ray diffraction, FE-SEM, EDS, Vickers hardness testing and Keithley high-strength electrometer. The deposits were synthesized in an inert atmosphere at room temperature. Subsequent, post-deposit thermal treatments were used at 500 ° C for 3 hours. The presence of the rutile and anatase phases were identified by XRD, where rutile was majority. The surface morphology was analyzed using FE-SEM where clusters of small particles with a size of 10 nm could be observed. Vickers hardness values reached 21.70 GPa, while electrical resistivity values showed a highly resistive behavior of 2.57 x1011 Ω.sq, which allows this material to be an excellent candidate for corrosion protection.

With the use of the sputtering technique, carbon incorporation was carried out on TiO 2 anodized with HCl. FE-SEM study revealed the formation of tubes and/or fibers nanostructures on the surface of the acquired samples. It was possible to identify the presence of carbon by vibrational modes and EDS analysis. The nanoindentation test demonstrated how the carbonincorporated TiO 2 samples improved the nanohardness and elastic modulus compared to titanium and TiO 2 anodized. The presence of carbon was able to reinforce the bond of the TiO 2 layer with the substrate, which improved adhesion and abrasive behavior, and in turn, reduced the friction coefficient up to 89% compared to titanium.