Droplet spreading and wettability of laser textured C-263 based nickel superalloy

Abstract

Nickel-based superalloy is commonly used in gas turbines, power plants, and aero-engine components due to its excellent wear resistance, resistance to corrosion, and high strength. However, this material suffers from poor oxidation resistance and short thermal cycling life. In the present study, nickel-based superalloy (C-263) was textured with four various waviness pattern combinations using picosecond Nd:YAG laser. The surface roughness and surface wetting behavior of the four waviness patterned specimens were investigated. The surface topographies were characterized using Scanning electron microscopy (SEM), X-ray photoelectron spectrometer (XPS), Energy dispersive spectroscopy (EDS), and 3D profilometer. Results showed that the textured surface significantly modifies the surface roughness of the deposited recast layers when compared to un-textured surface. Besides, features of hydrophilicity were observed on laser textured region under ambient condition. The elemental analysis suggested that power, frequency, scanning speed, and pulse overlapping greatly influenced the oxygen and carbon molecules formed after the laser ablation process, within a time period of 21 days. The XPS and EDS results revealed that the wetting property on the textured surface changed from hydrophilic to hydrophobic due to the presence of carbon and oxygen molecules. The corresponding water contact angle (WCA) for the different waviness grooved patterns were 132 ± 5°, 137 ± 3°, 141 ± 5°, and 128 ± 2°, respectively. In addition, there is no sliding movement of the water droplet was observed until 90° of contact angle hysteresis (CAH) due to the sticking or pinning effect of the water droplet on the textured surfaces. This outcome can be used to fabricate the desired C-263 based nickel super-alloy surfaces with hydrophobic property and therefore extend the applications of C-263 nickel alloy in various fields.