Corrosion inhibition of A3 steel by imidazoline derivative in 2·0%NaCl solution

The corrosion inhibition of A3 steel by an imidazoline derivative in 2%NaCl solution (pH 4·0-6·9) was investigated using weight loss method, potentiodynamic polarisation, electrochemical impedance spectroscopy and scanning electron microscopy (SEM) observations. It is suggested that the imidazoline derivative acts as an anodic type inhibitor, suppressing the charge transfer process by adsorption on the steel surface. The inhibition efficiency (IE) at pH 4·9 increases with the imidazoline derivative concentration in the range of 50-250 mg L⁻¹. Meanwhile, the IE for A3 steel in neutral solution is better than that in acidic solution. During a long time immersion, the IE increases first with the increasing immersion time. Although it decreases a little with further time extension, good inhibition performances are observed.