Effects of NO_2~- and NO_3~- Ions on Corrosion of AISI 4130 Steel in Ethylene Glycol + Water Electrolyte

摘要

The electrochemical behavior of steel alloy in ethylene glycol-water mixture was investigated by electrochemical methods. The results obtained showed that corrosion rate was decreased with increasing ethylene glycol concentration. The effect of nitrite and nitrate as inhibitor was studied and higher inhibition efficiency was obtained for nitrite. It was found that surface passivation occurred in presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl~- ions and the adsorption isotherm basically obeys the Flory-Huggins adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and reveal that the adsorption process is spontaneous.