PH-responsive anti-corrosion activity of gallic acid-intercalated MgAl LDH in acidic, neutral, and alkaline environments

Abstract

Undoubtedly, designing pH-responsive particles is one of the most fascinating aims for corrosion experts. Local pH variations can occur through the corrosion process (chemical and electrochemical reactions), accelerating the corrosion rate. However, by designing this class of modern inhibitors, a significant part of the effects of pH variation during corrosion disappears. Herein, a novel layer double hydroxide-based (LDH) nanocomposite, which is filled by gallic acid (GA) molecules, was designed. To prove the composite inhibition proficiency, EIS tests were conducted in acid, neutral and alkaline atmospheres and then surface morphology of the protected and unprotected samples are visualized by FE-SEM images. Simultaneously, the EDS-Mapping technique was applied to predict the elemental composition of the generated inhibitive layer. The results of the EIS test indicated an increase in corrosion resistance after using nanoparticles in all three acidic, neutral and alkaline environments. In addition, the potentiodynamic polarization test confirmed the mixed-protection mechanism in these three media. Furthermore, FE-SEM approach demonstrated the formation of a protective film on metal surfaces, and the EDS-Mapping evaluation confirmed these results in line with the element recognition.