Corrosion behaviour of mild steel in phosphoric acid medium with benzotriazole

Benzotriazole (13"1-A) was studied to investigate their inhibiting action on corrosion of mild steel in phosphoric acid (H3P0,) solution by mass loss and polar-ization techniques at 302K-333K. BTA showed very good inhibition efficiency. It has been found that the inhi-bition efficiency of the inhibitor increased with increase in inhibitor concentration and decreases with increasing temperature and also with increase in acid concentra-tions. The adsorption of the BTA on the mild steel surface from the acid has been found to obey Tempkin's adsorption isotherm. The values of activation energy (Ea) and free energy of adsorption (AGMs) were also calculated. The plots of log against time (days) at 302K give straight line which suggested that it obeys first order kinetics and also calculate the rate constant k and half life time t1„.