Understanding the Role of Superhydrophobicity and Superhydrophilicity in Salt‐Spray Corrosion of Nanosecond Pulsed Laser‐Textured AA2024 Alloy

Corrosion of aluminum alloys poses a significant challenge in the transportation and aerospace industries, where material degradation can lead to structural failure and increased maintenance costs. Yet, the corrosion performance of laser‐structured metallic surfaces exhibiting extreme wetting states under industrially relevant conditions remains largely unexplored. In this work, we investigate the competing roles of superhydrophobicity and superhydrophilicity in governing the corrosion behavior of laser‐textured AA2024‐T351 under salt‐spray conditions. Three different laser approaches were employed: direct laser interference patterning (DLIP), direct laser writing (DLW), and a modified version of DLW (DLWM). DLIP and DLWM generated line‐like periodic microstructures with spatial periods of 6 and 20 µm, respectively, both yielding saline contact angles (SCA) of 156 ± 1° and 151 ± 2°. In contrast, DLW produced a randomly textured superhydrophilic surface (SCA ≈0°). Regarding corrosion performance, the DLIP‐treated samples exhibited the highest resistance, with 95% reduction in pit density after 72 h of salt‐spray exposure relative to the reference surface. The superhydrophilic surfaces promoted the formation of larger pits due to longer electrolyte residence times, whereas superhydrophobicity confined corrosion to the microstructure. These findings highlight laser structuring as a versatile strategy for controlling wettability and extending corrosion lifetime under realistic conditions.