ABSTRACTThe array of the TiO2 nanotubular films, also called one-dimensional nanostructures is carried out by electrochemical anodization tests, for which, titanium sheets were used with a high purity (99.7% and 0.25 mm thickness) in a solution of deionized water and glycerol (50:50 vol.%) + 0.27M NH4F applying a voltage of 20V. Electrochemical tests were performed at an anodization time of 2:30 hours and 3:30 hours. For the tests mirror polished foils and unpolished foils with flat surfaces to achieve better uniform arrays during the anodic growth of nanotubes were used. After anodizing, samples were observed in the scanning electron microscope (SEM) to determine the geometry and morphology of the films. Also, potentiodynamic polarization curves were performed for samples crystallized at 600 °C and 450 °C (polished and unpolished) to determine the electrochemical stability of the films, which were presented at two aqueous solutions: 1M of Na2SO4 (pH= 6.7) and 1M Na2SO4 + H2SO4 (pH= 3.2). Mechanical characterization was also performed by nanoindentation technique through the application of loading/unloaings of: (1, 2.5, 5, 10 mN). Chemical characterization was performed using XRD analysis, with the aim to determine the crystalline phases formed in the films crystallized at 450 °C and 600 °C. The electrochemical characterization showed that the TiO2 nanotubular film obtained by mirror polished and crystallized at 600 °C showed better electrochemical stability. Nanoindentation tests showed deformation curves, and the parameters such as hardness, Vickers hardness, elastic modulus and the maximum penetration depth were determined as mechanical parameters.
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