Temperature effect on mild steel corrosion in acid media in presence of azoles

The inhibiting properties of four azoles (indole, benzimidazole, benzotriazole, benzothiazole) were investigated in case of mild steel corrosion in 1 M HCl. The effect of temperature was followed. Impedance spectroscopy, polarization resistance, gravimetric and polarization curves methods were applied. An adequate structural model of the interface in inhibitors presence is offered and the values of the corresponding parameters are calculated. The apparent activation energy of the process taking place in an inhibitor presence was determined on the ground of five temperature values in the range from 20 °C to 60 °C using the data obtained by two independent methods. Comparative investigations were carried out in 1 M H₂SO₄ aiming to elucidate the effect of the acid’s anion. The generalization of the data obtained provided to make conclusions concerning the mechanism of the inhibitors’ adsorption.