Fabrication And Anti-corrosion Properties Of Super-hydrophobic Films On Aluminum

Super-hydrophobic surface treatment technology, as a new environmentally friendly surface coating technology, has widely attracted researchers’ concerns both at home and abroad. Building a super-hydrophobic film on metal surface can improve the corrosion resistance of the metal. Hence, in order to enhance the corrosion resistance of aluminum, studying the preparation of super-hydrophobic membrane on the metal surface has far-reaching significance.In this paper super-hydrophobic surface is prepared through preparing micro/nano structures and chemical modification on the surface of aluminum, and its anti-corrosion properties are investigated as well.Firstly, Super-hydrophobic films with contact angle of160°were fabricated on aluminum by anodic oxidation method followed by chemical modification using octyl triethoxysilane. The parameters related to the preparation of super-hydrophobic surface, such as current density, concentrations of sulfuric acid and oxidation time were optimized. The crystal structure, morphology, composition and bond structure of super-hydrophobic surface were studied through XRD, SEM, EDX and IR spectra. The contact angle of optimum super-hydrophobic surface reached160°. The super-hydrophobic film enhanced the corrosion resistance of aluminum in3.5%NaCl solution.Secondly, the intermediate layers of ZnAl-LDH and MgAl-LDH with nano-structures are prepared on aluminum surface by hydrothermal method. It is found that the larger the concentration is, the denser the structure is. when Zn(NO3)2concentration is0.02mol/L and Mg(NO3)2is0.05mol/L, the contact angles are both beyond150°after chemical modification, which further improved the corrosion resistance of Al metal..Finally, we obtain the micro/nano structure of the Mg-Al hydroxides through galvanic deposition method. The contact angle of the super-hydrophobic film is far beyond150°after chemical modification by triethoxysilane. Electrochemical tests show that the corrosion resistance of aluminum was effectively increased by3orders of magnitude in3.5%NaCl solution.