A new method for preparing Mg-Al-layered double hydroxides coating using supercritical CO2 fluid

Abstract

A new method for preparing Mg-Al-layered double hydroxides (Mg-Al-LDHs) coating using supercritical CO2 fluid was developed. The morphologies, structures, compositions, and corrosion resistances of the surface coatings were investigated. Unlike traditional methods, the method using supercritical CO2 fluid generated ultrafine nanocrystal coatings with an average size of 30 nm, and a thickness of ca. ∼ 11 μm. The Mg-Al-LDHs coating was mainly composed of C, O, Mg, and Al. Corrosion resistance measurements show that the amount of hydrogen evolution for the nanocrystal LDHs coating was only 0.133 mL·cm−2, the polarisation resistance was 3174.9 Ω·cm2, and the immersion test corrosion grade of 7G. Finally, the formation mechanism of the Mg-Al-LDHs coating under supercritical CO2 fluid was proposed.