Experimental Research on the Fabrication and Wettability of Micro- and Nano-scale Surface Textures Produced on Stainless Steel Using an Ultrafast Laser
Y-Q. Wang, H-F. Yang, J-B. Hao, Q-G. Han, L. Fang and S-R. Ge
Micro- and nano-scale surface textures on a stainless steel sample fabricated by ultrafast laser radiation have been seen to be influenced by the irradiating energy which is determined by laser power, scanning velocity and number of times of repeat scanning. The experimental results showed that one typical periodic submicron ripple, whose periodicity changed with scanning velocity, was obtained when the irradiating energy was lower than the critical damage laser energy value. Another typical multiscale complex structure consisted of micron protrusions, submicron dimples and submicron short ripples, which were obtained when the irradiating energy was higher than the critical damage laser energy value. Wettability experiments revealed that the apparent contact angles on the surfaces of original stainless steel sample, the periodic submicron ripples and the multi-scale textures were 114°, 148° and 162°, respectively. The results showed that two kinds of micro- and nano-scale surface textures on the stainless steel sample surface induced by the ultrafast laser radiation all had super-hydrophobic properties, with the multi-scale texture being more super-hydrophobic property than the periodic submicron rippled surface.
Keywords: Ti: sapphire laser, ultrafast laser, surface texture, micro-scale, nano-scale, fabrication, wettability, energy irradiation, scanning velocity