Formation process and microstructure of TiO2 nanotube arrays prepared by anodization

In order to control the morphologies of TiO2 nanotube arrays, it is significant to investigate the effects of anodization parameters on the formation process and the microstructure of nanotube arrays. Titanium (99.6%) was anodized in 0.1-1.0 wt% HF solutions by using Pt as cathode in this work. Anodization process was carried out at voltage range from 0.4 V to 14.5 V and solution temperature from 5C to 40C. The linear sweep anodic polarization curve and current density-time curves were obtained by means of electrochemical workstation. The morphology of the oxide films was observed with SEM. The effects of time, anodizing voltage, solution temperature on the formation process and the microstructure of titania arrays were studied, respectively. The results show that the growth rate, the nano-pore diameter and the thickness of titania film are obviously affected by anodic oxidation condition, which increased with increasing voltage. But the higher, the voltage, the longer, the time, to achieve balanced growth. It is also found that a higher solution temperature or a higher HF concentration is beneficial to improve the growth rate, shorten the time to equilibrium and reduce the steady nanotube length at equilibrium stage. © 2009, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.