Transition from superhydrophilic to superhydrophobic state of laser textured stainless steel surface and its effect on corrosion resistance

摘要

This work investigates the evolution from superhydrophilic to superhydrophobic surface state on corrosion behaviour of SS316L produced by Nd:YAG nanosecond direct laser texturing (DLT). Results confirm perfect correlation among wettability and corrosion, hence superhydrophobic surface with a contact angle of 168 +/- 3.0 degrees reflects in enhanced passivity, lower anodic dissolution and corrosion current reduction. Characterization of the corrosion attack by 3D microscopy reveals high sensitivity of superhydrophilic surfaces on corrosion propagation direction in regard to the laser beam passage (90 degrees/0 degrees). However, this trend completely diminishes with superhydrophobic development. Further, DLT also completely prohibits intergranular corrosion detected with the non-processed sample.