Tribological Properties of a Laser Textured Superhydrophobic TC4 Ti Alloy Surface
J-L. Guo, F. Wang, J.J. Liou and Y-H. Liu
Superhydrophobic TC4 Ti alloy is essential for economical use in modern machinery. Herein, a novel superhydrophobic pattern textured TC4 Ti alloy surface with a self-assembled molecular film was fabricated by an efficient nanosecond laser ablation (laser surface texturing (LST)) and a facile chemical modification method. Further, the transformation of the surface morphology and chemical composition was analysed. Upon adjusting the laser fluence, scanning velocity and scanning distance, the maximum water and saline contact angles of the laser surface textured and chemically treated surface reached 155.5 ±0.8° and 152.5 ±1.3°, respectively. The tribological behaviour of the patterned surfaces was investigated under dry-sliding and liquid-sliding conditions. High density textures exhibited the greatest potential for lubrication under water and saline lubrication conditions. In a dry environment, a scattered-line pattern textured surface also showed a friction reducing effect, similar to that under saline sliding conditions. Finally, the anti-wear mechanism was further explained considering the morphology and wettability.
Keywords: Nanosecond fibre laser, TC4 Ti alloy, laser surface texturing (LST), morphology, wettability, superhydrophobicity, coefficient of friction (CoF)