CORROSION INHIBITION EFFICIENCY OF PHENANTHROLIN ON GRAYCAST IRON IN HYDROCHLORIC ACID

In the present work, the inhibitive properties ofphenanthrolin were investigated in case of corrosion of gray castiron in 1N HCl solution. The effect of the temperature was alsoexamined. Polarization curves and electrochemical impedancespectroscopy methods were recorded, an adequate model of theinterface in the presence of inhibitor is proposed and the valuesof the corresponding parameters are calculated. The apparentactivation energy of the process taking place in the acid andinhibitive solutions, was determined. The obtained results showedthat phenanthrolin effectively reduces the corrosion rate of thisiron alloy. Indeed, the inhibition efficiency (E %) of thiscompound increases with the concentration increase and attainsa maximum value of 94% at 400 ppm. However, the temperaturerise slightly decreases the inhibition efficiency of phenanthrolinagainst the corrosion of the ferrous alloy. This phenomenonsuggests the involvement of a chemical adsorption of theinhibitive molecules on the metal surface.Keywords: cast iron, corrosion inhibition, phenanthrolin, acid.