Effect of the incorporation of montmorillonite-layered double hydroxide nanoclays on the corrosion protection of epoxy coatings

A series of layered double hydroxide (LDH)/montmorillonite (MMT) nanocomposite coating, LDH nanocomposite coating, and MMT nanocomposite coating were successfully prepared. The nanocomposite materials were characterized by X-ray diffraction and scanning electron microscopy (SEM). To understand the effect of MMT and LDH on the corrosion inhibition performance of epoxy resin coatings immersed in 3.5 wt% saline solution at 90A degrees C, electrochemical impedance spectroscopy and an autoclave test were performed on epoxy resin; epoxy resin blended with LDH, MMT, and LDH + MMT (LM) coatings painted on Q345 steel. The metal/coating interfaces were observed by SEM and energy-dispersive spectroscopy. Results showed that addition of LDH and MMT improved the protection properties of the epoxy resin coatings. The corrosion protection of the LM nanocomposite coating was superior to that of the other coatings. This finding can be attributed to the ionic selectivity and barrier effect of MMT and LDH nanoclay platelets dispersed within the composite coatings.