Adsorption mechanism of quaternary ammonium corrosion inhibitor on carbon steel surface using ToF-SIMS and XPS

ToF-SIMS and XPS are combined to study the adsorption of tetradecyl-benzyldimethyl-ammonium (BDA-C14) bromide corrosion inhibitor on carbon steel surface. BDA-C14 forms a protective layer with N-containing polar head group interacting with carbon steel surface. The adsorbed inhibitor surface coverage strongly depends on immersion time and inhibitor concentration. A maximum and uniform coverage is found for sufficiently long exposure times at a critical inhibitor concentration of about 25 ppmw. The uniform adsorbed inhibitor layer formed on the surface mitigates the formation of iron chloride/hydroxide intermediates and thus enhances the corrosion protection of carbon steel in aggressive environment.

Automated summary

ToF-SIMS and XPS techniques were used to investigate the adsorption behavior of BDA-C14 corrosion inhibitor on the carbon steel surface. The inhibitor formed a protective layer with N-containing polar head group interacting with the surface. The coverage of adsorbed inhibitor varied with immersion time and inhibitor concentration, and reached a maximum and uniform value at a critical concentration of about 25 ppmw. The formation of iron chloride/hydroxide intermediates was mitigated by the uniform adsorbed inhibitor layer, leading to enhanced corrosion protection of carbon steel in aggressive environment.