Abstract
T HE CORROSION behaviour of a cadmium electrode in Na2CO3 and HCl solutions was studied in the absence and presence of five compounds of cationic surfactants of olyelamido derivatives using potentiostatic polarization technique. The inhibition efficiency was found to increase with increasing the inhibitor concentration and the number of polyethylene diamine units, and decrease with rising temperature. These compounds are more effective in HCl than in Na2CO3 solutions. This can be attributed to the synergistic effect of Cl- ions with the cationic surfactant compounds. The inhibitors are adsorbed on the surface of Cd in both HCl and Na2CO3 solutions according to Langmuir adsorption isotherm. The effect of temperatures was studied to evaluate some activated thermodynamic parameters.