Modification of wetting property of Inconel 718 surface by nanosecond laser texturing

Abstract

Topographic and wetting properties of Inconel 718 (IN718) surfaces were modified via nanosecond laser treatment. In order to investigate surface wetting behavior without additional post treatment, three kinds of microstructures were created on IN718 surfaces, including line pattern, grid pattern and spot pattern. From the viewpoint of surface morphology, the results show that laser ablated grooves and debris significantly altered the surface topography as well as surface roughness compared with the nontreated surfaces. The effect of laser parameters (such as laser scanning speed and laser average power) on surface features was also discussed. We have observed the treated surface of IN718 showed very high hydrophilicity just after laser treatment under ambient air condistion.And this hydrophicility property has changed rapidly to the other extreme; very high hydrophobicity over just about 20 days. Further experiments and analyses have been carried out in order to investigate this phenomena. Based on the XPS analysis, the results indicate that the change of wetting property from hydrophilic to hydrophobic over time is due to the surface chemistry modifications, especially carbon content. After the contact angles reached steady state, the maximum water contact angle (WCA) for line-patterned and grid-patterned surfaces increased to 152.3  1.2° and 156.8  1.1° with the corresponding rolling angle (RA) of 8.8  1.1° and 6.5  0.8°, respectively. These treated IN718 surfaces exhibited superhydrophobic property. However, the maximum WCA for the spot-patterned surfaces just increased to 140.8  2.8° with RA above 10°. Therefore, it is deduced that laser-inscribed modification of surface wettability has high sensitivity to surface morphology and surface chemical compositions. This work can be utilized to optimize the laser processing parameters so as to fabricate desired IN718 surfaces with hydrophobic or even superhydrophobic property and thus extend the applications of IN718 material in various fields.

Insights into the wettability transition of nanosecond laser ablated surface under ambient air exposure

“…However, many previous studies have reported that just after laser ablation, the fresh ablated metal surface was hydrophilic or super-hydrophilic with the presence of micro/nanostructures. When the laser ablated surface was exposed to the ambient air for a relatively long time, the wettability transition from super-hydrophilic to super-hydrophobic could be observed [12][13][14][15][16][17][18][19][20]. Recent research efforts have been directed towards the explanation of the wettability transition mechanism.…”

Fabrication of super-hydrophobic nickel film on copper substrate with improved corrosion inhibition by electrodeposition process

“…Generally, super-hydrophobic surfaces present a water contact angle (WCA) over 150° with the lotus effect (rolling angle (RA) below 10°) or the pinning effect (no RA or RA above 10°) [5][6]. Studies on natural creatures with super-hydrophobic surfaces reveal that the presence of micro/nanostructured surface morphology is the main cause for constructing special surface wettability [7][8][9].…”

“…So far, many different techniques have been proposed to successfully achieve bioinspired super-hydrophobic surface through modifying surface morphology and surface chemical compositions including chemical vapor deposition [13]. sol-gel [14], chemical etching [15], laser surface texturing [8][9][10]16], thermal embossing [17] and electrodeposition [18], etc. However, the first three mentioned techniques are limited due to expensive equipment, tedious chemical treatments and complicated multi-step processing procedures [19][20].…”

Wettability of CNW/ITO Micro Structure for Modification of Surface Hydrophilicity

“…The wettability is one of the surface properties which is settled by molecules and the area distributed at the boundary surface of carbon nanomaterials and liquids with a range from nm to um, and alteration of the molecules-area with a surface structure of carbon nanomaterials is efficiently able to affect wettability. As methods for change of wettability, various techniques modifying the surface structure and components have been employed [8][9][10][11]. In this regard, and compared with the surface structure of carbon nanomaterials mentioned above, graphene and CNT are horizontal against the substrate.…”