The inhibition effect of schiff base synthesized from allantoin molecule on carbon steel corrosion in hydrochloric acid solution

The effect of (E)-1-(2-hydroxy-5-methoxybenzylidene)-3-(2,5-dioxoimidazolidin-4-yl) urea (ALMS) on corrosion behaviour of mild steel in 1.0 M HCl has been investigated as depending on concentration and temperature. The corrosion inhibition efficiency of ALMS has been evaluated by using potentiodynamic polarization curves, linear polarization resistance and electrochemical impedance spectroscopy techniques. According to findings corrosion rates decrease and percentage inhibition efficiencies and surface coverage degrees increase with increasing additive concentration. Corrosion resistances of inhibited solutions were mainly resulted from adsorption of ALMS molecule on mild steel surface. Activation energies of corrosion reaction in 1.0 M HCl and all concentrations of inhibitor have been calculated. ALMS molecule appears to function through the Langmuir adsorption isotherm. Thermodynamic adsorption parameters of studied molecule were calculated using adsorption isotherm. The results of SEM and AFM measurements indicate that Schiff base is adsorbed on metal surface and metal is protected against corrosion.