Waterborne robust superhydrophobic PFDTES@TiO2-PU coating with stable corrosion resistance, long-term environmental adaptability, and delayed icing functions on Al–Li alloy

Aluminum–Lithium (Al–Li) alloys widely used in aerospace manufacture are highly susceptible to corrosion, which limits their industrial applications. Herein, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) is used as a modifier for low-surface-energy treatment of TiO2 nanoparticles. The water-based polyurethane (PU) is made as a binder to achieve a tight bonding between modified ceramic particles and Al–Li alloy, thus resulting in the extremely-feasible air-spraying preparation of a superhydrophobic coating with strong abrasion resistance. The water contact angle (CA) of as-prepared coating achieves 160 ± 0.83°, and the rolling angle (SA) is as low as 5.95 ± 0.59°. The surface structure, organization and composition are further characterized using SEM, EDS, XPS and laser confocal microscopy. Meanwhile, the electrochemical impedance and potentiodynamic polarization tests are performed for corrosion characterization. The results show that the corrosion potential of such coating increases by 170 mV compared with substrate, the corrosion current density decreases by two orders of magnitude, and the impedance modulus increases by two orders. The corrosion inhibition rate of the as-prepared coating is 98.8%, indicating that the corrosion resistance has been significantly enhanced. In addition, the mechanical robustness and stability of the coating is evaluated and confirmed using a sandpaper rubbing test. It also possesses great self-cleaning, anti-pollution and thermostable behaviors, thereby allowing them to work in extreme manufactures. Moreover, the as-prepared coating exhibits excellent adaptability to various materials and anti-icing property. This work sheds positive insights in enlarging industrial applications of multifunctional ceramic coatings in aerospace fields.