Nitrogen-Containing Organic Inhibitors of Corrosion

Abstract

A quantitative relation between the cathode potential rise with the addition of inhibitor and its inhibition efficiency is suggested and proved. The difference in functions between nitrogen-containing organic inhibitors and cathodic inorganic inhibitors is pointed out.

Adsorption from Solution of Stearic Acid on Iron: Effect on Electrode Potential

“…Most of the potential shift in the noble direction occurs at stearic acid concentrations less than 10-3 M. At higher concentrations, the change is very gradual and the potential tends to come to a constant value. Similar results have been reported for steady-state potentials of steel in acid solutions containing various corrosion inhibitors (15,16,17). All potentials referred to hereafter are those for steady state.…”

Action of Polar Organic Inhibitors in Acid Dissolution of Metals

“…Essential features of this theory (6,31,32,33) are that organic inhibitors are capable of forming onium ions and accordingly exiet in acid solution as cations.…”

Use of an imidazol synthetized from palm oil as a corrosion inhibitor for a supermartensitic stainless steel in H2S

“…The loop diameter increases as the inhibitor concentration increases, reaching its highest value with an inhibitor concentration of 25 ppm, decreasing when the inhibitor concentration increases to 50 and 100 ppm. On the other hand, Bode diagrams, Figure 9 b, indicates that the impedance value reaches its maximum value at an inhibitor concentration of 25 ppm, increasing from a values of 100 ohm cm 2 obtained in the uninhibited solution up to a value higher than 7,000 ohm cm 2 at 25 ppm, which is due to the adsorption of the inhibitor on the metal surface (46,47). This increase in the impedance value in presence of the inhibitor is due to the formation of a protective layer due to the reaction of the inhibitor and metal ions released during the corrosion reaction.…”