Fabrication of oriented layered double hydroxide films by spin coating and their use in corrosion protection

MgAl-Layered Double Hydroxide (LDH) films have been prepared by spin coating a nanodispersed MgAl-LDH sol on an AZ31 magnesium alloy substrate. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) of the as-prepared films demonstrated their uniform and compact structure composed of LDH platelets stacked parallel to the substrate surface. The anti-corrosion properties of the LDH films were investigated by measuring dc polarization curves and electrochemical impedance spectroscopy (EIS). EIS results demonstrated that the densely packed oriented LDH platelets are effective in restricting penetration of aggressive ions and thus inhibit corrosion of the underlying metal surface. The corrosion resistance imparted by the LDH films increased with film thickness. (C) 2008 Elsevier B.V. All rights reserved.