In-situ construction of grass-like hybrid architecture responsible for extraordinary corrosion performance: Experimental and theoretical approach

Abstract

Despite the engineering potential by the co-existence of inorganic and organic substances to protect vulnerable metallic materials from corrosive environments, both their interaction and in-situ formation mechanism to induce the nature-inspired composite remained less understood. The present work used three distinctive mercapto-benzazole (MB) compounds working as corrosion inhibitors, such as 2-mercaptobenzoxazole (MBO), 2-mercaptobenzothiazole (MBT), and 2-mercaptobenzimidazole (MBI) in a bid to understand how the geometrical structure arising from O, S, and N atoms affected the interaction toward inorganic layer. MB compounds that were used here to control the corrosion kinetics would be interacted readily with the pre-existing MgO layer fabricated by plasma electrolysis. This phenomenon triggered the nucleation of the root network since MB compounds were seen to be adsorbed actively on the defective surface through the active sites in MB compound. Then, the molecule with twin donor atoms adjacent to the mercapto-sites affected the facile growth of the grass-like structures with ‘uniform’ distribution via molecular self-assembly, which showed better corrosion performance than those with having dissimilar donor atoms with the inhibition efficiency (η) of 97% approximately. The formation mechanism underlying nucleation and growth behavior of MB molecule was discussed concerning the theoretical calculation of density functional theory.