Surface Characterization of Thin Titanium Foils Processed by Femtosecond Laser Ablation in Liquids

Laser ablation in liquids offers some key advantages over conventional laser processing under gaseous or inert conditions. A significant volumetric reduction of the heat affected zone minimizes the risk of damaging adjacent regions during processing. Due to complex physicochemical interactions the interactions in the ablation zone and their impact need to be investigated. For this study, titanium was chosen as a base material, as it is widely used in a broad range of micromachining applications. The results of the change of ablation rate, surface roughness and surface oxidation for thin titanium foils in both purified water and argon are presented and compared respectively. Processing in the much denser liquid medium reveals differences in the fluence dependant ablation characteristics and an overall reduction in the ablation rate, supposedly caused by plasma -shielding. Favourable aspects are given by the higher surface quality and improved dimensional tolerances, making the process a promising alternative in micromachining applications.