Multi-step synergistic approach for preparation of aluminium superhydrophobic coatings

Abstract

In this study, a multi-step synergistic process combining chemical etching, hydrothermal deposition and stearic acid modification was proposed for the corrosion protection needs of aluminium alloys in marine environments, and micro- and nano-composite superhydrophobic coatings (STZ) were successfully constructed on the surface of aluminium bases. Scanning electron microscopy, EDS, and XRD confirmed the presence of zinc oxide particles with micron-level rough structures on the coating surface. Contact angle testing showed a static contact angle of up to 156° and a rolling angle of less than 5°, which is consistent with superhydrophobic properties. Electrochemical tests showed that the corrosion current density of the STZ coating was three orders of magnitude lower than that of the untreated substrate, and the charge transfer resistance was significantly higher, confirming a significant increase in corrosion resistance. After 400 linear abrasion cycles, the coating retained 70% of its hydrophobic properties. In self-cleaning tests, the rate of contaminant adhesion was reduced by 75% compared to the untreated substrate.This process provides a feasible solution for the long-term protection of aluminium alloys in harsh environments.