Ultra-durable ZIF-7 superhydrophobic coating for long-term corrosion protection in aircraft nacelles lips

The aviation industry's rapid development highlights aircraft metal corrosion, especially for parts like nacelle lips exposed to varying environments, greatly impacting flight safety. In this paper, we propose a “sandwich” superhydrophobic anticorrosive coating containing ZIF-7, which utilizes nanocontainer technology to achieve rapid environmental response. ZIF-7-encapsulated corrosion inhibitor releases during corrosion, preventing leakage and coating damage. In addition, a superhydrophobic coating has been added on top of the anticorrosive coating, which has been imparted with a surface water contact angle of up to 154 ± 3° and a water sliding angle of about 3°. It also has excellent physical/chemical stability, and it remains superhydrophobic even after repeated mechanical abrasion and acid/alkali immersion. The double-layer structure not only further enhances the ‘labyrinth effect’ and extends the path for corrosive media to reach the metal surface, but also successfully isolates water and oxygen from the surface of the coating, which significantly improves the coating's functionality and anticorrosion performance. The highest impedance modulus of 1.3931 × 10 11  Ω·cm 2 is 10 7 fold higher than that of the bare Al alloy sheet. After 30 days of salt spray experiments to accelerate the corrosion rate, the bare Al alloy sheet corroded significantly smaller on the fifth day, while the ZB/ZnO did not undergo significant changes, and healing occurred at the scratches. Our study introduces ZIF-7 to the field of corrosion protection by superhydrophobic coating, providing insights into practical applications and the field of aircraft lip corrosion protection.