Adsorption and corrosion inhibition properties of pyridine‐2‐aldehyde‐2‐quinolylhydrazone for Q235 steel in acid medium: Electrochemical, thermodynamic, and surface studies

Abstract

A new organic compound pyridine‐2‐aldehyde‐2‐quinolylhydrazone (PAQ) was synthesized and its structure was characterized by 1 H NMR and FTIR spectroscopy. The inhibition effect of PAQ on the Q235 steel corrosion was investigated with potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM)/energy dispersive X‐ray spectroscopy (EDX), and scanning electrochemical microscope (SECM). The inhibition mechanism was further studied in view of the effect of inhibitor concentration and temperature on the corrosion of steel. Polarization studies showed that the PAQ acted as a mixed‐type inhibitor. The adsorption of PAQ inhibitor on Q235 steel surface follows Langmuir adsorption isotherm and contains both physical and chemical type adsorptive. The formation and characteristic of protective layer on the steel surface were verified by surface analysis techniques (SEM, EDX, SECM).