Recently, laser polishing, as an effective post-treatment technology for metal parts fabricated by laser powder bed fusion (LPBF), has received much attention. In this paper, LPBF-ed 316L stainless steel samples were polished by three different types of lasers. The effect of laser pulse width on surface morphology and corrosion resistance was investigated. The experimental results show that, compared to the nanosecond (NS) and femtosecond (FS) lasers, the surface material’s sufficient remelting realized by the continuous wave (CW) laser results in a significant improvement in roughness. The surface hardness is increased and the corrosion resistance is the best. The microcracks on the NS laser-polished surface lead to a decrease in the microhardness and corrosion resistance. The FS laser does not significantly improve surface roughness. The ultrafast laser-induced micro-nanostructures increase the contact area of the electrochemical reaction, resulting in a decrease in corrosion resistance.

A tunable coffee-ring effect (CRE) that enables the patterned deposition of nanoparticles (NPs) is obtained on a designed superhydrophilic and superhydrophobic composite surface of a titanium substrate. Low-adhesion superhydrophobic surfaces with picosecond laser-induced periodic surface structure and micro–nano hierarchical structure are investigated. The NPs are not only deposited in a small area of $0.045{\mathrm{mm}}^2$, which is 265.56 times smaller than that of the original hydrophilic surface, but also in various patterns such as triangular, rectangular, and ecliptical besides the traditional circular shape. This controllable morphology of the CRE indicates a maneuvering capability of NPs in their common preservation form of suspension turbid liquid, even when the solution concentration reaches 1 mg/mL, which is promising for NP-printed circuit boards and site-specific delivery drugs.

The commensurate contact condition plays a key role in the directional friction properties and wear performance when two surfaces slide against each other. An experimental study on bidirectional friction and wear control by nanosecond pulsed laser selective texturing of grooves on AISI 304 stainless steel (SS) and TA2 titanium (Ti) surfaces of the sliding components was proposed. The influence of the aspect ratio (AR) and groove orientation angle on directional friction properties and wear performance was investigated. The AR₂ and 75° samples performed best with 68.13 and 21.71% overall average coefficient of friction reduction for the Ti–Ti and SS–SS interfaces, respectively. The AR_5.5 generated the least wear for the Ti–Ti and SS–SS pairs. The results take us a step closer to deriving a more effective, accurate, and dependable guideline for designing laser-machined surface grooves for directional sliding friction control.