Preparation and Application of Calcined Mg/Al Layered Double Hydroxides in Organic Coatings and Chloride Removal

Abstract

The adsorption of infiltrated chloride ions by layered double hydroxide (LDH) is expected to improve the corrosion resistance of organic coatings. Mg/Al layered double hydroxide (LDH) with a Mg/Al molar ratio of 4:1 was prepared using the co-precipitation method. The calcined layered double hydroxide (CLDH) was placed in NaCl solution to investigate its effect upon the adsorption of Cl-, then, the product was added to a two-component epoxy coating, to study its effect upon corrosion resistance. The CLDH powder product was characterized using XRD and FT-IR, and the corrosion resistance of the coatings was investigated by EIS and NSS tests. The experimental results show that CLDH can effectively adsorb Cl- from a NaCl solution via its memory effect, and the corrosion resistance of the epoxy coating can be improved by adding 1.0-2.0 wt. % CLDH.