Nanosecond Laser Surface Texturing of AISI 316L Stainless Steel for Capillary Transport

Laser-textured stainless-steel surfaces are candidates for passive liquid transport in thermal-management devices. This study compares groove, dimple, and wobble process recipes on 0.5 mm AISI 316L, with line-step screening within each recipe. The highest reported central-area roughness was Sa = 70.5 µm for W2. Under a 25-day protocol involving daily water-contact-angle measurements followed by isopropyl-alcohol rinsing and drying, D3 and W2 initially exhibited complete spreading and reached apparent water contact angles of 115° and 105°, respectively, on day 25; G3 varied between 56° and 77°. Among the three specimens selected for hydraulic testing, the reported G3 values combined K ≈ 2.5 × 10−11 m2 with an effective pore radius of approximately 29 µm, whereas the roughest specimen, W2, had the lowest reported permeability. These exploratory observations identify G3 as a candidate for further capillary-surface development.