One-step fabrication of oriented Mg/Al-layered double hydroxide film on magnesium substrate with urea hydrolysis and its corrosion resistance

This work presents a simple and direct method for synthesizing Mg/Al-layered double hydroxides (MgAl-LDHs) film on an Mg sheet by in situ hydrothermal crystallization with urea hydrolysis, and protecting the Mg sheet from corrosion. The morphology and structure of the LDHs film were characterized by scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy, respectively. A uniform and compact thin film was formed, of which the LDHs platelets were highly oriented with their ab-face perpendicular to the Mg substrate. XRD pattern and FT-IR spectrum show that MgAl-LDHs film was formed accompanied with Mg(OH)2. Polarization measurements showed that the LDHs film exhibited a low corrosion current density value of 10−6 A/cm2. The strong adhesion between the film and the substrate was observed by cross-cutting method. These results indicated that the LDHs film can effectively protect Mg sheet from corrosion.