On the adjustment of pH with lower amines in carbon dioxide corrosion of steels

The corrosion behavior of steel CT3 under conditions of continuous and peri odical wetting in a carbon dioxide medium (p(CO2) = 1 atm) was studied. The effect of some neutralizers (NaOH; primary, secondary, and tertiary lower amines; ethylenediamine; and monoethanolamine) on the carbon dioxide corros ion of steel was determined. An analysis of the pH dependence of the protec tive effect shows that the basicity is an important but not always dominant property of neutralizing amines. Depending on their structure, they can ch ange the kinetics of electrochemical reactions in one way or another, thus significantly contributing to the protection of steel. Compounds containing mono- and disubstituted amino groups were found to be the most effective i nhibitors.