Microstructure and mechanical properties of nanostructured and microstructured TiO2 films

In this study, we present results of comparative studies on the microstructure and mechanical properties of nanostructured and microstructured titanium dioxide (TiO2) films formed on titanium substrates by electrochemical anodization at different electrolytes. Nanostructured TiO2 film was prepared in 1% HF solution for 30 min. Microstructured TiO2 films were anodized in two different electrolytes (1 M H2SO4 and 1.4 M H3PO4) for 10 min. The phase structures, surface morphologies and surface topographies of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively. The surface hardness and elastic modulus of the TiO2 films were studied using nanoindentation technique. The results showed that the electrolyte type and applied voltage have a strong influence on the morphology and crystalline structure of the TiO2 films. It was found that hardness and elastic modulus of the nanostructured TiO2 film were much lower than the microstructured TiO2 films.