Study on the corrosion inhibition performance of quinoxaline corrosion inhibitor on Q235 steel in 1M HCl solution

Abstract

Abstract Mild steel is widely used in many fields of production life, and it is of great practical significance to inhibit its corrosion in relevant corrosive media. Quinoxaline (Q) and its derivative diphenyl(quinoxaline-2-yl)phosphine oxide (QP) were selected as corrosion inhibitors for Q235 steel in 1.0 M HCl solution using weight loss and electrochemical analysis methods. The results showed that these synthesized additives possessed good anticorrosion efficiency for Q235 steel in HCl media, and as the concentration of the inhibitor increases, the inhibition effect becomes better and better. The inhibition efficiency of Q and QP reached the highest value at the concentration of 1 × 10− 3 M, they are all hybrid corrosion inhibitors. The inhibition efficiency of QP was greater than that of Q, which was related to the fact that diphenylphosphine can enhance the adsorption capacity with Q235 steel. The EIS plots showed that charge transfer resistance increased and double-layer capacitance decreased with increasing the concentration of studied inhibitors due to the adsorption of inhibitor molecules on the Q235 steel surface. The adsorption of these inhibitors on the carbon steel surface conforms to the Langmuir adsorption isotherm. Surface characterization of the corrosion inhibitor-impregnated and non-impregnated for the carbon steel samples using scanning electron microscopy (SEM) and UV-visible spectroscopy showed that a barrier film was formed on the Q235 steel surface to prevent contact with the corrosive medium.