Scaling the productivity of laser structuring processes using picosecond laser pulses at average powers of up to 420 W to produce superhydrophobic surfaces on stainless steel AISI 316L

Abstract

We investigate the approach to scale up the productivity of the laser-based generation of superhydrophobic surfaces by means of increased average laser powers to enhance the surface structuring rates. Polished surfaces (mean roughness depth SRz = 0.076 μm) of stainless steel AISI 316L were processed with a laser delivering 8 ps long pulses with a constant pulse energy of 1.4 mJ at pulse repetition rates of 100 kHz or 300 kHz corresponding to average laser powers of 140 W or 420 W, respectively. When the feed rate for the corresponding pulse repetition rate is adjusted in a way to result in a similar temperature increase due to heat accumulation effects and the re-deposition of nanoparticles formed during processing is avoided, comparable surface structures with similar wetting behavior are obtained.