An-Najah Staff

The behaviour of C-steel in molar hydrochloric acid solution in the presence of Extract (CAE) was investigated using weight loss measurements, potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results obtained reveal that the aggressiveness of hydrochloric solution was considerably decreased in the presence of the CAE. The inhibition efficiency was found to increase with increase in the concentration of the natural substances tested. Potentiodynamic polarization studies clearly reveal that the presence of CAE does not change the mechanism of the hydrogen evolution reaction and they act essentially as cathodic inhibitors. The temperature effect on the corrosion behaviour of C-steel is studied in the range from 298 to 328K without and with at 0.1 g/l. The adsorption isotherm of natural product on the steel has been determined. The apparent activation energies, enthalpies and entropies of the dissolution process were discussed.