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.
Glucose electrooxidation in alkaline solution was examined using glassy carbon electrodes modified with Au nanoparticles. Au nanoparticles were prepared following the two-phase protocol and characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction spectroscopy (XRD), and cyclic voltammetry (CV). It was found that, under the study conditions, it is possible to obtain nanoparticles between 1 and 5 nm; also it was found that the crystallographic orientation is strongly influenced by the ratio metal/thiol and to a lesser extent by the synthesis temperature. The voltammetric response for the electrocatalytic oxidation of glucose at carbon Au nanoparticle-modified electrode shows an increasing activity with nanoparticles size. Electroactivity and possibly selectivity are found to be nanoparticles' crystallographic orientation dependent. Classical electrochemical analysis shows that glucose electrooxidation is a diffusion-controlled process followed by a homogenous reaction.
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.
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