Corrosion Inhibition Mechanism of Imidazoline-Based Dissymmetric Bis-Quaternary Ammonium Salts with Different Hydrophobic Chain Length on Q235 Steel in 1 M HCl Solution

The surface properties of a series of imidazo-line-based dissymmetric bis-quaternary ammonium (DBA) salts with different hydrophobic chain lengths DBA-12, DBA-14 and DBA-16 were determined. The adsorption behaviors of these compounds in 1 M HCl solution and their inhibitive effect on Q235 steel (U12350) were investigated using the weight-loss method, polarization, and electrochemical impedance spectroscopy. Results indicate that the three inhibitors all showed good inhibition performance for Q235 Steel in 1 M HCl solution and were found to be mixed-type inhibitors. The adsorption behavior of the three inhibitors can fit the Langmuir isotherm equation and the values of Delta G(ads)(0) are around or lower than 40 kJ mol(-1), indicating that there is a stronger chemical adsorption.