Yingdong Li

Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy

Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.

A facile approach to superhydrophobic LiAl-layered double hydroxide film on Al–Li alloy substrate

A highly oriented LiAl-layered double hydroxide (LDH) film was first fabricated via a facile in situ growth method on Al–Li alloy. The morphology and structure of the LDH film were characterized using scanning electron microscopy, atomic force microscopy, X-ray diffraction, and transmission electron microscopy. After chemical modification with 1H,1H,2H,2H-Perfluorodecyltrimethoxysilane, the chemical compositions and states of surface-modified film were analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results showed that the nest-like structure of LiAl-LDH film was composed of interconnected LiAl-LDH nanosheets, which oriented almost vertically to the substrate surface. After chemical modification, a superhydrophobic surface was obtained with water contact angle of 168°. The formation mechanism of the superhydrophobic film was also discussed.

Enhancement of active anticorrosion via Ce-doped Zn-Al layered double hydroxides embedded in sol-gel coatings on aluminum alloy

Ce-doped Zn-Al layered double hydroxide (LDH) nanocontainer was synthesized by a co-precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods were used for the characterization of the LDH nanocontainer. The anticorrosion activity of the LDH powders embedded in a hybrid sol-gel coating on aluminum alloy 2024 was investigated by electrochemical impendence spectroscopy (EIS). The results showed that Ce (III) ions were successfully incorporated into LDHs layers. The sol-gel coating modified with Ce-doped Zn-Al LDHs exhibited higher anticorrosion behavior compared with both unmodified and Ce-undoped LDHs containing coatings, which proved the applicability of Ce-doped LDHs in delaying coating degradation and their potential application as nanocontainers of corrosion inhibitors in self-healing coatings.