Corrosion of Alloy Steel in 30% Ethylene Glycol Solution and CrO42− Under Hydrodynamic Condition

The electrochemical behavior of steel alloy in 30% ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements. The results obtained showed that corrosion rate did not change significantly at different rotating speeds. The effect of chromate as the inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of the inhibitor. The inhibiting effect of the chromate was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and results reveal that the adsorption process is spontaneous.