Fabrication of hydrophobic Ti3SiC2 surface with micro-grooved structures by wire electrical discharge machining

The near-superhydrophobic Ti3SiC2 surfaces with regular and controllable micro-grooved structures were fabricated by wire electrical discharge machining (WEDM). The surface topographies and chemical compositions of smooth and micro-grooved Ti3SiC2 surfaces were characterized. The micro removal mechanism of Ti3SiC2 in the process of electrical discharge machining was also analyzed. The wetting mechanism of micro-grooved Ti3SiC2 surface was discussed along with the static contact angle, anisotropic wettability and contact angle evolution versus time. The relationships between parallel and perpendicular contact angles, depth-width ratio of micro-grooved structures and surface roughness of textured surface were investigated. The experimental results show that the parallel contact angle on the textured Ti3SiC2 surface increased by about 164% compared with the one on the smooth surface, and near-superhydrophobic surface with obvious anisotropy was roughly achieved. The experimental parallel contact angles were very close to theoretical contact angles calculated by Cassie-Baxter formula. It is confirmed that the depth-width ratio may be used to predict the parallel contact angle with the average prediction error of 2.4%. The perpendicular contact angles had a good correlation with the depth-width ratio and surface roughness.