Inhibition Effect of Some Organic Compounds Toward the Corrosion of Steel Electrode in Citric Acid Solution in presence of Chloride Ions

The chemistry behavior of steel electrode in acid solutions has been studied by galvano static polarization technique. The consequences of concentrations of acid and temperature of solution are examined. It was found that greater the citric acid concentration or reducing of temperature of the solution assist the passivation process. The values of icorr decreased with greater concentrations of citric acid solutions and lowering of the temperature of solution. The free activation energy of passive film formed is determined and found to be 7.45 kJ/mole. Addition of increasing concentrations of some aggressive anions such as Cland SO4 — was also investigated. With increasing concentrations of those anions result in the destruction of the passive film due to the increasing of corrosion current density, icorr, and therefore the shift of corrosion potential, Ecorr, to more negative potentials. Trials had been made to inhibit the corrosion process via including a few organic compounds as, urea, phenylhydrazin and 1,2-phenylenediamine.