Abstract
• Xanthium coriander corrosion inhibitor can effectively reduce the corrosion current and increase the corrosion potential. Its adsorption behavior conforms to the Frumkin adsorption theory. • The corrosion inhibition mechanism is as follows: the adsorption active site of 1,5-dicaffeoylquinic acid is phenolic hydroxyl oxygen, and the phenolic hydroxyl oxygen on the surface of Fe (1 1 0) hybridizes with the 3d empty orbital of Fe to form a covalent bond. • Carboxylic acid group of 1,5-dicaffeoylquinic acid is ionized, and there is a tight bond between the oxygen atom in the –COOå − group and the calcium ion to form a coordination complex. • Xanthium cocklebur corrosion inhibitor has the functions of retarding, strengthening and rusting, and the optimal concentration is 2 g/L. • Under the optimal concentration, the proportion of residual strength of steel fiber reinforced concrete is about 10% higher than that of steel fiber reinforced concrete without corrosion inhibitor. Aiming at the corrosion inhibition mechanism of Xanthium japonica corrosion inhibitor and its comprehensive influence on concrete performance, this paper carried out in-depth exploration through potentiodynamic polarization curve method, XPS and SEM and other detection methods, combined with quantum chemical calculation and molecular dynamics simulation. The study found that the Xanthium cocklebur corrosion inhibitor can effectively reduce the corrosion current and increase the corrosion potential. It is a composite corrosion inhibitor. Its adsorption behavior conforms to the Frumkin adsorption theory, and can form a relatively stable adsorption film on the surface of carbon steel, with global adsorption characteristics. The corrosion inhibition mechanism is as follows: the phenolic hydroxyl oxygen of 1,5-dicaffeoylquinic acid hybridizes with the 3d empty orbital of Fe to form a covalent bond; the hydroxyl hydrogen and the hydroxyl oxygen on the surface of γ-FeOOH (0 1 0) are connected by hydrogen bond. Xanthium cocklebur has the functions of retardation, enhancement and rust inhibition, and the optimal concentration is 2 g/L. The mechanism of retardation is that phenolic acid molecules contain complex forming groups, which can form coordination complexes with calcium ions in an alkaline environment, and control the concentration of calcium ions in the pore liquid of steel fiber reinforced concrete in the early stage of hydration.
Published Version
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