Anti-corrosion performance of superhydrophobic nanoparticle-modified hybrid coatings on AZ31B magnesium alloys

Corrosion resistance is a critical challenge for magnesium alloys, particularly AZ31B, in aerospace, military, and biomedical applications. This study investigates the anti-corrosion performance of superhydrophobic SiO₂ NPs-modified PTFE/PUA hybrid coatings on AZ31B, fabricated using rod and spray painting techniques. The coatings exhibited excellent superhydrophobic properties, with contact angles exceeding 155° and a contact angle hysteresis (CAH) below 5° Electrochemical evaluations of superhydrophobic SiO₂ NPs-modified PTFE coatings demonstrated a reduction in i corr by four orders of magnitude compared to that of raw AZ31B Mg alloys, achieving a corrosion inhibition efficiency (η p ) of ∼ 99.9 % in a 3.5 wt % NaCl solution. The E corr shifted positively by 0.968 V and 1.022 V, respectively. Additionally, the R ct of the SiO₂ NPs-PTFE hybrid coatings increased by four orders of magnitude compared to blank PTFE-0-R coatings, indicating robust and enhanced corrosion resistance. The study also found minimal differences in corrosion protection based on fabrication technique, while SiO₂ NPs-PUA coatings showed limited effectiveness in corrosion resistance. These findings highlight the potential of superhydrophobic PTFE hybrid coatings in addressing corrosion challenges for magnesium alloys.