Femtosecond Laser-Induced Spike Topographies on Nickel-Based Alloys: In Situ Labeling, Growth Mechanism, and Anti-Icing Performance

Creating spike topographies on nickel-based alloys through laser structuring is anticipated to enhance their functionality and improve surface performance. Recent efforts aimed at developing ice-phobic surfaces have primarily focused on introducing spike-like structures; however, the mechanisms underlying the formation of spikes remain elusive. Here, an in situ labeling method is proposed to directly trace the evolution of spike structures at their original sites. This method provides a clear depiction of the evolution process, including the inception of undulating structures, the growth of voids, and the reproduction of voids. The roles of undulating structures and voids in the development of spikes are identified, and the energy modulation effect has been confirmed through experimental results and numerical models. The preparation method offers high stability in fabricating spike topographies on nickel-based alloys, and the protrusion size can be finely tuned by adjusting the pulse energy. Finally, potential applications of the surface covered with spikes are demonstrated. The measured contact angles and sliding angles indicate that the laser-structured surface exhibits good hydrophobic properties, and the surface with larger protrusions demonstrates excellent anti-icing performance. The time required to complete icing on laser-structured surfaces can be up to ≈3.3 times that of the original surface.