Two tetrazole compounds were synthesized. The prepared compounds were identified by CHNS analysis FT-IR and 1H-NMR spectroscopy. The inhibition efficiency in the presence of tetrazoles as a steel corrosion inhibitor in 0.5M HCl calculated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Results obtained revealed that tetrazole compounds performed excellently as a corrosion inhibitor for C-steel in this medium and its efficiency attains to 91.34% at 5x10-3M at 303 K by potentiodynamic polarization measurements and 91.66% by EIS in the same conditions. The surface morphology studies (SEM and AFM) showed that these types of inhibitors had a smooth surface with deposited compounds on it for the specimen that treated with acidic inhibited solutions as compared with the surface of those specimens which treated with uninhibited acidic solution.
C-steel corrosion, tetrazole, EIS, surface morphology