Anticorrosion organic coating with layered double hydroxide loaded with corrosion inhibitor of tungstate

Mg–Al layered double hydroxides, loaded with tungstate anions, were synthesized via the co-precipitation method. The obtained compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), inductively coupled plasma (ICP), and transmission electron microscopy (TEM), respectively. The ICP results demonstrated the partial anion-exchange process, involving the release of tungstate anions from layered double hydroxide by the chloride anions. Polarization measurements showed that the filtrate as electrolyte possessed a low corrosion current density value of 3.042 μA/cm2. The electrochemical impedance spectroscopy (EIS) exhibited that the coating could effectively protect the alloy from corrosion. The function of the layered double hydroxide loaded with tungstate doped in organic coating was also discussed.

► Mg–Al layered double hydroxides loaded with tungstate anions were successfully synthesized.
► The released tungstate from LDH-WO42− powders is a new environmentally friendly corrosion inhibitor.
► The epoxy coating containing LDH-WO42− powders could effectively protect the alloy from corrosion.