Texturing of metallic surfaces for superhydrophobicity by water jet guided laser micro-machining

• Published in: Applied surface science 2020-01, Vol.500, p.144286, Article 144286
• Main Authors: Shi, Yi, Jiang, Zilin, Cao, Jian, Ehmann, Kornel F.
• Format: Article
• Language: English
• Subjects: Superhydrophobicity; Surface texturing; Water jet guided laser processing; Wetting
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.144286

[Display omitted] •Fabrication of functional surfaces by water jet guided laser micro-machining.•Stable superhydrophobic property is achieved on stainless steel surfaces.•Surface morphology and chemistry define the wettability of metallic surfaces. This experimental work demonstrates a new cost-effective way of achieving superhydrophobicity on metallic surfaces by micro-texturing with a novel water jet guided laser process. Compared to conventional pure laser texturing by nanosecond, picosecond and femtosecond lasers, water jet guided laser processing yields textures with an almost zero heat affected zone while the debris on the textured surface is simultaneously cleaned by the jet during the process. The effects of grid spacing, laser power coupled into the jet and water jet diameter are examined and processing conditions for achieving superhydrophobicity are provided. Changes in the wetting of the surface over time under ambient conditions from hydrophilic to superhydrophobic, due to changes in surface chemistry, were explored. It has been shown that the surface contact angle dramatically increases within the first couple of days after texturing when exposed to air. After around 20 days, the contact angle stabilized at 150°, 130° and 129° on textured 304 stainless steel, titanium and 6061 aluminum surfaces, respectively.