The Inhibition Behaviour of some 1,2‐azole derivatives for the corrosion of mild steel in sulphuric acid solutions

Abstract

AbstractThe corrosion inhibition of mild steel in sulphuric acid solutions by two series of 1,2‐azole derivatives was studies by using weight loss, polarization and capacitance measurements. Series 1 derivatives were 3‐methy1‐5‐amino‐1,2‐azoles (azole = pyrazole, isoxazole and isothiazole) and series 2 derivatives were 3(5)‐amino‐5(3)[4′‐X‐phenyl]pyrazoles (X = H‐, Cl−, NO2−, Me− and MeO−). The effect of inhibitor concentration, temperature, acidity and chloride ion concentration on the inhibition efficiency was also investigated.The inhibition was found to increase with increase of the inhibitor concentration and decrease of temperature, acidity and chloride ion concentration. Generally, the inhibition efficiency was found to increase with increase of the azole basisity and the electron density on the azole ring. The inhibition occurs through adsorption of the inhibitor molecules onto the metal surface following Temkin isotherm. The nature of the inhibitive species and the modes of adsorption were discussed.