Synergistic Corrosion Inhibition Effect of a Compound Inhibitor for Aluminum
The corrosion inhibition behavior of 4-mercaptopyridine(4MP),sodium dodecyl sulfate(SDS),and compound inhibitor 4MP-SDS for aluminum in 3.5％NaCl solution was comparatively investi-gated via experimental test and digital simulation.The results show that the presence of corrosion inhibi-tor could effectively reduce the free-corrosion current density.Moreover,the increase dosage of corrosion inhibitor has a positive effect on the enhancing desorption potential of corrosion inhibitor.The corrosion in-hibition efficiency of the three inhibitors may be ranked as 4MP+SDS＞SDS＞4MP.The mass loss test results show good agreement with the electrochemical test results.After the injection of compound inhibi-tor,a corrosion inhibitor film can form on the metal surface.Thus,the resistance to the diffusion and mi-gration of corrosive ions increased and the corrosion rate of Al slowed down,correspondingly,the Al sur-face maintains a good metallic luster and shows the characteristics of a uniform corrosion pattern.In addi-tion,the anti-corrosion mechanism of the compound inhibitor 4MP+SDS was revealed by molecular dy-namics(MD)simulation.The compound inhibitor 4MP+SDS showed greater ability to slow down the build-up of interfacial water layers,increase the surface coverage,and the bonding effect is more stable,compared with the presence of a single 4MP or SDS,demonstrating the strong adsorption of the com-pound inhibitor on Al,while the best anti-corrosion performance.
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