Synthesis characterization and corrosion inhibition efficiency of N-C2 {(2E)-2-[4-(dimethylamino) benzylidene] hydrazinyl} 2-oxo ethyl benzamide on mild steel

In the present paper, we report the synthesis of N-C2{(2E)-2-[4-(dimethylamino) benzylidene] hydrazinyl} 2-oxo ethyl benzamide (DMB) as a potential inhibitor of mild steel. The study of inhibition effect of DMB on the mild steel in 1.0 N H2SO4 solution has been carried out using weight loss, galvanostatic polarization and electrochemical impedance spectroscopy (EIS) techniques. The polarization curves showed that DMB compound behaves as both cathodic and anodic inhibitor, i.e. a mixed type inhibitor. EDX and SEM observations of the mild steel surface confirmed existence of a protective adsorbed film of the inhibitor on the mild steel surface. The temperature dependent studies from 298–318 K showed that the DMB adsorption follows the Langmuir isotherm model. The value of activation energy (Ea) for mild steel corrosion and thermodynamic parameters such as adsorption heat (ΔHads), K and ∆G0ads have been calculated and discussed. It has been found that the protection efficiency increases with increasing inhibitor concentration in the range of 250–1000 ppm, but slightly decreases with increasing temperature. The graphs obtained from TGA indicate relatively good thermal stability of the inhibitor film on the metal surface. The results show that DMB is good corrosion inhibitor for mild steel in acidic medium.