A facile approach for wettability transition to enhance the hydrophobicity of Ti6Al4V alloy using laser surface texturing

Abstract

Ti6Al4V has been widely used in important sectors such as biomedical, automobile, and aerospace engineering. Apart from superior mechanical properties, the Ti6Al4V must also possess self-cleaning ability. The self-cleaning ability of any material can be enhanced by imparting hydrophobic characteristics. In the current research work, laser surface texturing technique has been used to make linear and cross-hatched (CH) structures over the Ti6Al4V samples. Compared to the plain sample, the CH sample significantly enhanced the hydrophobic nature of Ti6Al4V by substantially increasing the water contact angle to the value of 141°. As compared to the plain sample, the contact angle value was found to be 70% more in the CH sample. The formation of rutile TiO₂ film in textured samples can be considered the reason for the enhanced hydrophobicity. The increase in the peak of rutile TiO₂ film in textured samples has been observed through the XRD analysis. Upon the point EDX analysis, it has been observed that the amount of oxygen increased approximately 10 times in the textured sample as compared to the plain sample. Further, upon droplet impact testing high recoil height and droplet separation height have been observed for the textured sample. The CH sample has provided a recoil height of 5.25 mm. The recoil height for the CH sample has been found to 3.5 times more than that of the plain sample. The CH sample also provided the droplet separation height of 9.3 mm, whereas the droplet separation phenomenon was found to be absent for the plain sample. Overall, high contact angle, formation of rutile TiO₂ film, and enhanced droplet recoiling phenomena indicate that the facile method such as laser texturing can successfully impart high hydrophobicity to the Ti6Al4V samples.