Electrochemical synthesis and hydrophobic modification of ZnAl–LDHs films on Q235 steel for corrosion protection

Purpose This study aims to optimize electrodeposition parameters for ZnAl–layered double hydroxides (LDHs) films on Q235 steel and modify them for enhanced corrosion protection. Design/methodology/approach ZnAl–LDHs films were electrodeposited on Q235 steel. Key parameters (pH, Zn2+/Al3+ ratio, potential, time) were optimized via univariate and orthogonal experiments. Films were then modified with perfluorodecyltrimethoxysilane (PFDTMS) for superhydrophobicity. Morphology, structure, wettability and corrosion resistance were characterized by SEM, XRD, FTIR, contact angle and electrochemical tests in 3.5 Wt.% NaCl. Findings Optimal parameters: c(Zn2+):c(Al3+)=2:1, pH = 3.8, −1.5 V, 600 s. The ZnAl–LDHs film showed good crystallinity and corrosion resistance. After PFDTMS modification, it became superhydrophobic (contact angle 160°, sliding angle 2.1°), with significantly enhanced corrosion resistance maintained after 10 days immersion, demonstrating durable protection. Originality/value A facile, efficient and green electrodeposition method was developed for ZnAl–LDHs films on carbon steel, with parameters optimized via combined univariate/orthogonal experiments, offering an effective strategy for protective coatings.