Corrosion inhibition performance and adsorption mechanism of new synthesized symmetrical diarylidenacetone-based inhibitor on C38 steel in 15 % HCl medium: Theoretical insight and experimental validation

Abstract

Despite the engineering potential of using organic substances to protect vulnerable metallic materials from corrosive environments, the interaction mechanisms and adsorption processes that lead to the formation of hybrid materials remain poorly understood. Further research is necessary to elucidate how these organic compounds interact with metallic surfaces and the specific pathways through which they adsorb to form protective layers. Understanding these mechanisms is crucial for developing more effective corrosion-resistant hybrid materials, which could significantly enhance the properties of metallic components and provide excellent electrochemical stability in various industrial applications. This work aims to explore the corrosion performance and interfacial mechanism of two symmetrical diarylidenacetone-based compounds, namely, (1E,4E)-1,5-bis(4-methoxyphenyl) penta-1,4-dien-3-one (MPD) and 2,6-di((E)-benzylidene) cyclohexan-1-one (BZC), in a bid to control the corrosion kinetics of C38 steel in aggressive environment. This assessment integrated experimental, surface, and theoretical explorations. The results of our study revealed the remarkable ability of MPD and BZC molecules to generate a dense, resistant protective film on the C38 steel surface. This protective film acted as a barrier, effectively blocking the penetration of corrosive ions and their interaction with the C38 substrate. The inhibition efficiencies of the investigated products exhibited a consistent rise with increased amounts of additives. The inhibition efficiency reached 95 % for MPD and 90 % for BZC at 10−3 M, as calculated from the fitting Nyquist diagrams. The interaction between the inhibitor and Fe(110) was studied utilizing density functional tight binding (DFTB) and Molecular dynamics simulations (MDS). The results demonstrate the formation of covalent bonds, with the molecules aligning in a parallel orientation of MPD and BZC. This alignment with experimental findings provides strong validation for the efficacy of the inhibitors in corrosion inhibition.