Inhibition Behavior of Imidazoline Phosphate Compound Inhibitor on Q235 Steel in Hydrochloric Acid Medium

• Published in: Corrosion (Houston, Tex.) Vol. 67; no. 4; pp. 45005 - 45005-7
• Main Authors: ZHANG, J, GONG, X.-L, YU, H.-H, DU, M
• Format: Journal Article
• Language: English
• Published: Houston, TX NACE International 01.04.2011
• Subjects: Adsorption; Analytical methods; Applied sciences; Corrosion; Corrosion environments; Corrosion inhibitors; Corrosion potential; Corrosion prevention; Efficiency; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes; Electron microscopy; Exact sciences and technology; Free energy; Hydrochloric acid; Imidazoline; Inhibitors; Iodides; Killed steels; Laboratories; Metals. Metallurgy; Phosphates; Potassium; Potassium iodide; Potassium iodides; Scanning electron microscopy; Software; Spectroscopy; Spectrum analysis; Steel; Structural steels; Submerging; Temperature; Hydrochloric acid; Phosphates; Imidazole derivatives; Absorption; Corrosion; acid inhibitors; Carbon steel; polarization; Corrosion protection; Acid medium; Corrosion inhibitor
• ISSN: 0010-9312; 1938-159X
• DOI: 10.5006/1.3573550

The inhibitive effect on Q235 steel and the adsorption behavior of a compound inhibitor, including imidazoline phosphate (IPI) and potassium iodide (KI), were studied in 1 mol/L hydrochloric acid (HCl) solution using the weight-loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Results showed that the inhibition efficiency increased with an increase in inhibitor concentration, and temperature had no significant effect on inhibition efficiency. The compound inhibitor was a mixed-type inhibitor that mainly inhibits cathodic processes. The best inhibition efficiency was obtained at an immersion time of 120 h. The adsorption of the compound inhibitor on Q235 steel could be fitted to a Langmuir isotherm and the values of the adsorption free energy ΔGads are close to −40 kJ/mol over the studied temperature range. The adsorption process is a spontaneous chemical adsorption.