Corrosion inhibition of 2-amino-5 ethyl-1 , 3 , 4-thiadiazole on mild steel in hydrochloric acid *

Corrosion inhibition of mild steel in 0.5M hydrochloric acid solutions by 2amino5 ethyl1, 3, 4-thiadiazole(TTD) was studied using weight loss, open circuit potential measurement and potentiodynamic polarization technique. The compoundshowedmaximum inhibition efficiency of 93.7 and 97% at highest TTD concentration from weight-loss and potentiodynamic polarization test. Results from corrosion potential monitoring showed the inhibiting compound well within passivation values throughout the exposure period.Inhibition efficiency varied with inhibitor concentration and the mechanism of inhibition is attributed to chemical interaction and adsorption form thermodynamic calculations. Adsorption of the compound obeyed the Langmuir and Frumkin isotherm model. Scanning electron microscopy characterization showed the formation of protective precipitates on the steel surface while statistical derivations confirmed the overwhelming statistical significance of inhibitor concentration against exposure time on inhibition efficiency.