The effect of laser ablation on the corrosion behavior, morphology and wettability of TiAlCrSiZr coating deposited by PVD

This work investigates the surface properties, corrosion resistance, and wettability of a laser-ablated TiCrAlSiZr high-entropy alloy coating deposited on SS316L via cathodic arc evaporation (CAE). The GIXRD patterns of the as-deposited coatings indicated a hexagonal-Ti 3 Al single-phase microstructure that changed drastically when being subjected laser irradiation. This new structure, resulting from laser ablation, showed a cauliflower like morphology with nanostructure features, resulting in superhydrophobicity toward polar solutions and hydrophilicity toward nonpolar solutions. This differential contact angle is attributed to changes in surface roughness and chemical composition induced by the laser irradiation. Moreover, the water contact angle of laser irradiated samples increased with days passing owing to the absorption of carbon complexes. Analysis revealed a finer grain size and the presence of a more stable passive layer in the laser-irradiated region, contributing to the enhanced hydrophobicity and a 35 % decrease in corrosion current density compared to the as-deposited coating. This improved corrosion resistance is directly linked to the superhydrophobic effect, which minimizes contact between the corrosive electrolyte and the coating surface, thereby inhibiting penetration of the corrosive agents.