Work

In-situ grown Mg-Fe-inhibitor-LDH conversion film on steel for improving corrosion protection in the chloride contaminated environment

Year: 2025

Type: article

Abstract: Use of layered double hydroxide (LDH) conversion films is an effective method for enhancing the corrosion protection of metals, which has been extensively studied on non-ferrous metals. Steel, being the most commonly used engineering material , would significantly benefit from such technology if LDH films could be formed on its surface. In this study, an Mg-Fe-pAB-LDH conversion film is successfully grown in situ on Cr-alloy steel. The properties of the Mg-Fe-pAB-LDH film and its precursor Mg-Fe-CO 3 -LDH film are characterized using SEM, XRD , EDS , XPS , and electrochemical methods . The results show that both LDH films are composed of cross-linked blade-like flakes oriented perpendicular to the substrate, with numerous intersecting voids. The incorporation of pAB − inhibitor ions and CaCO 3 by-products into LDH film significantly improves its corrosion resistance in chloride-contaminated environments. The inhibition efficiencies of the Mg-Fe-pAB-LDH film in 0.1, 0.3, and 0.6 mol/L NaCl solutions are 99 %, 97 %, and 68 %, respectively. This superior protection is attributed to three primary mechanisms: physical barrier of LDH film with CaCO 3 particle, chloride absorption into LDH flakes, and release of inhibitor ions from LDH film. Typically, the Mg-Fe-pAB-LDH film have a Cl − adsorption capacity of 0.368 mol/m 2 and a pAB − release capacity of 0.217 mol/m 2 . Meanwhile, the corrosion protection performance decreases as the chloride concentration increases, indicating that the LDH film used for high-chloride environments need further optimization.

Source: Materials Today Communications

DOI: 10.1016/j.mtcomm.2025.112488