Tuning surface wettability of aluminum surface and its correlation with short and long term corrosion resistance in saline solutions

In this work, we fabricated superhydrophilic aluminum alloy (AA 6063) with a hierarchical labyrinth-like structure using a facile and environmentally benign chemical etching method. The patterned samples were functionalized by stearic acid molecules to obtain superhydrophobic samples with water contact angle (CA) >160 degrees, at optimum conditions. Although the superhydrophobic samples initially exhibited up to two orders of magnitude better corrosion resistance compared to as-received samples, their corrosion performance and CA gradually reduced upon prolonged exposure to 3.5 wt% NaCl solution. Hence, we experimetally show that the initial high CA in superhydrophobic surface layers cannot be used as a measure of their long-term corrosion stability.

Automated summary

In this study, we fabricated superhydrophilic aluminum alloy (AA 6063) and obtained superhydrophobic samples through functionalization. However, the corrosion resistance and water contact angle of the superhydrophobic samples gradually reduced upon prolonged exposure to salt solution, indicating that the initial high contact angle cannot be used as a measure of long-term corrosion stability.