Synthesis and Mechanical/Electrochemical Characterization of TiO2Nanotubular Structures Obtained at High Voltage

A M Vera-Jiménez,R M Melgoza-Alemán,C Cuevas-Arteaga,M G Valladares-Cisneros

doi:10.1155/2015/624073

A M Vera-Jiménez, R M Melgoza-Alemán + Show 2 more

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https://doi.org/10.1155/2015/624073

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Abstract

The synthesis of TiO2nanotubular arrays obtained through anodization of Ti foils in ethylene glycol (3% volume DI H2O + 0.25 wt.% NH4F) at high voltage is reported. The physical, chemical, electrochemical, and mechanical characterization was made to the TiO2nanotubular arrays. The morphological characterization showed a cylindrical geometry (112 nm inner diameter and 65 μm length), determining a rugosity factor of 1840 points. The electrochemical characterization was carried out exposing four samples: Ti, TiO2amorphous, and two crystalline TiO2nanotubular arrays (450 and 600°C) in two aqueous solutions of different pH: 1 M Na2SO4and 1 M Na2SO4+ H2SO4, using the potentiodynamic polarization curves. The mechanical characterization was performed through the nanoindentation technique applying three different loads (2.5, 5.0, and 10 mN) on the amorphous and the two crystalline TiO2nanotubular samples, obtaining the mechanical parameters such as the hardness, the elastic module, and the maximum penetration depth. The TiO2nanostructured sample crystallized at 600°C had the best electrochemical stability in both media and presented an elastic modulus of 22.42 GPa when it was tested applying a load of 2.5 mN, whereas the amorphous sample presented the major hardness at the loads of 5 and 10 mN.

Highlights

The TiO2 nanotubular arrays have caused great interest because of their high area/volume relationship and the new properties due to their nanometric size
It is important to mention that titanium dioxide is a semiconductor, which acts as a good photocatalyst in presence of UV radiation [2]
Electrochemical anodization experiments were performed in a nonaqueous electrolytic solution of ethylene glycol (3 vol.% H2O) + 0.25 wt.% NH4F

Summary

Introduction

The TiO2 nanotubular arrays have caused great interest because of their high area/volume relationship and the new properties due to their nanometric size. The TiO2 nanotubular films have shown to have many applications, especially due to their high oxidation potential, chemical stability, and low toxicity in animals and human beings [1]. TiO2 can be found in its three allotropic forms: brookite, rutile, and anatase; the last two, but the phase anatase, present a major photocatalytic activity [3, 4]. The nanostructured TiO2 possesses certain desirable mechanical properties, such as high hardness and wear resistance, which becomes an attractive material for the fabrication of tools exposed in continuous motion and abrasion [5, 6].

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