Exploring the inhibitive performance of amino-dicarbonitrile derivative for Q235 steel protection in Cl₃CCOOH solution: effect of temperature and synergism with iodide ions

The inhibitory performance of amino-dicarbonitrile derivative (ANC) for the protection of Q235 steel corrosion in trichloroacetic acid (Cl₃CCOOH) solution was investigated using various methods. The surface adsorption of ANC was screened by SEM, AFM, and XPS methods. Based on the data, it can be concluded that ANC effectively inhibits Q235 steel in 0.5 M Cl₃CCOOH solution, with 94.3 % inhibition efficiency (η%) at 100 mg/L. The Freundlich model describes how ANC adsorbs on the surface of Q235 steel. Anodic and cathodic reactions are both retarded by ANC, a mixed type inhibitor. The depressed capacitive loop observed is the Nyquist diagram. The double layer capacitance decreases but the charge transfer resistance rises noticeably with the addition of ANC. The AFM and SEM micrographs provide unambiguous confirmation of the effective inhibition of ANC. The XPS result shows that ANC molecules functional groups are attached to the iron atoms.