Inhibition performance and adsorption behaviour of dodecylamine on N80 steel in CO2‐saturated brine solution

PurposeThis paper seeks to investigate the different inhibition performance and adsorption behaviour of dodecylamine in acidic and neutral environments and to understand further the inhibition mechanism of dodecylamine in CO2‐saturated brine solution.Design/methodology/approachThe inhibition performance and adsorption behaviour of dodecylamine on N80 steel in CO2‐saturated brine solution in acidic and neutral environments were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy and the attenuated total reflection‐Fourier transform infrared spectroscopy.FindingsCorrosion potentials exhibited a pronounced shift in the positive direction at higher concentrations of dodecylamine. The inhibition efficiency of dodecylamine was shown to be pH‐dependent. The effective inhibition concentration of dodecylamine decreased from pH 4.9 to 7.4. In a neutral environment, the inhibitor was shown to affect the deposition of the corrosion products and provide more active sites to bond with the inhibitor. More alkaline environments made the electron cloud density of dodecylamine much higher, which was more favourable to the interaction of dodecylamine and the naked metal base, and hence dodecylamine had a much better inhibition performance in a neutral environment than in acidic environments.Originality/valueThis paper provides information regarding the inhibition performance and adsorption behaviour of dodecylamine on N80 steel and probes the inhibition mechanism of dodecylamine in acidic and neutral environments. The results of the work contribute to an understanding of the inhibition mechanism of the inhibitor in different environments, which will be useful for effective design and choice of inhibitors in CO2 corrosion.