Effect of Ultrasonic Waves on the Formation of TiO2 Nanotubes by Electrochemical Anodization of Titanium in Glycerol and NH4F

The present work describes the anodic growth of self- organized TiO2 nanotubes TiNT) on titanium samples in an electrolyte containing 3% NH4F and 5% H2O in glycerol. Two stages anodization were proceeded. Initially, the potential was ramped from 0V to 30, 40 and 60 V. In the second stage the potential was held at the given potential up to 5 hrs. The application of ultrasonic waves during anodization was found to increase the reaction rates as it decreased the concentration gradient of the anodization products around the electric double layer. This resulted in high current and faster growth rates of the nanotubes. The diameters of the TiNT created under ultrasonic wave condition were found to be smaller than the corresponding TiNT created under magnetic stirring. However, the morphology of the TiNT was badly affected as a result of surface perturbation resulting from heterogeneity in surface energy density. A better route for good looking TiNT is to grow them under magnetically stirred solution followed by cleaning by sonication in deionized water for 30 seconds. Increasing the anodization potential from 30 to 60 V increased the dimensions of the TiNT from around 90 nm to around 150 nm, respectively.