Superhydrophobic Silane/Fluorinated Attapulgite@SiO₂ Composite Coatings on Magnesium Alloy for Corrosion Protection

Abstract

To improve the corrosion resistance of magnesium alloys, superhydrophobic coatings were prepared by employing fluorinated attapulgite@SiO2 (F‐ATP@SiO2) particles and silanes via a facile one‐step spraying technique in this study. Surface morphology, chemical compositions, roughness and wettability of the coatings were comprehensively investigated by Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectra (FTIR), 3D optical microscope and contact angle techniques, respectively. Corrosion resistance of the coatings was evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). Results indicated that the coatings exhibited superhydrophobicity due to its micron scale mastoid structure and low surface energy of F‐ATP@SiO2 particles. The superhydrophobicity and anticorrosion performance of the coatings increased with the dosage increase of F‐ATP@SiO2 particles. The water contact angle of the prepared surface can reach as high as 161° with sliding angle of 4°. Icorr of the coatings can reach 5.519×10−8 A cm−2, decreased by 3 orders of magnitude compared to bare AZ31, which showed excellent anticorrosion performance. With the prolongation of immersion time, the EIS analysis indicated that the anticorrosion property of the coating degraded gradually. Based on the electrochemical analysis, the corrosion protection mechanism of the superhydrophobic coating was proposed.

Superhydrophobic and Photothermal PVDF/CNTs Durable Composite Coatings for Passive Anti‐Icing/Active De‐Icing

“…There were two reasons for this phenomenon, on the one hand, the addition of PVDF induced the formation of micro‐nanostructures, which would create more multi‐level pore structures with higher R a and hierarchical structures (shown in Figure 4d,f). On the other hand, it was due to the FAS‐17 treatment, which led to reducing surface energy [ 47–50 ] of the PVDF/CNTs coatings surface and the adhesion of water droplets. In addition, liquids such as ethylene glycol, glycerol, paraffin oil and milk cannot wet the surface of the coating (shown in Figure e).…”

Advances in the Modification of Silane-Based Sol-Gel Coating to Improve the Corrosion Resistance of Magnesium Alloys

“…Other nanoparticle fillers (such as silica particles [ 83 , 84 ]) were also able to be incorporated with sol-gel coatings. Wang et al combined the sol-gel system with fluorinated attapulgite particles (FATP@SiO 2 ) to prepare a superhydrophobic surface on the AZ31 Mg alloy (ATP is an inexpensive magnesium-aluminosilicate-rich clay mineral with nanorod-like crystal morphology and reactive -OH groups on the surface) [ 85 ]. The water contact angle of the prepared surface was as high as 161° with a sliding angle of 4°.…”

Investigation of Electrochemical Assisted Deposition of Sol-Gel Silica Films for Long-Lasting Superhydrophobicity

“…A schematic diagram of the described reaction process is shown in Figure 1 a. It is worth noting that during the above “electrodeposition” process, the silane component does not lose or gain electrons at the electrode surface and the pH value of the bulk solution itself does not change throughout the process, and no new substances are introduced [ 31 , 32 , 33 ]. Compared to conventional self-assembled films, these electrodeposited films (e-films) have several unique advantages: (i) The base catalysis near the cathode surface provides an additional driving force for film formation, resulting in thicker and rougher films [ 34 , 35 ]; (ii) Gelation is separated from solvent evaporation and occurs during electrodeposition, producing films with greater porosity and better intra-film cohesion; (iii) The derived OH- ions also catalyze the chemical bonding process between the sol-gel film and the substrate [ 36 ].…”