A comparative study of the corrosion inhibition of low carbon steel in HCl solution by an imine compound and its cobalt complex

• Inhibitory effect of both imine and its cobalt complex rose as their concentrations increased.
• The imine is an anodic controlled mixed type inhibitor whereas its cobalt complex is cathodic.
• The adsorption of complex on steel surface has more chemisorption nature than the imine compound.
• The inhibition efficiencies are 97.6% and 97.8% for the imine and complex after 120 h.

The inhibition ability of an imine compound (PTM) and its cobalt complex (CoPTM) towards low carbon steel (LCS) corrosion in HCl solution was studied at various concentrations and temperatures using potentiodynamic polarization curves (Tafel), electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) methods. Electrochemical measurements showed that the inhibition efficiencies of both PTM and CoPTM depend on concentration, temperature, and immersion time. An adsorption mechanism for PTM and CoPTM on the LCS in 1 M HCl solution was proposed and discussed. Electrochemical results confirmed that the adsorption of CoPTM was stronger than PTM.

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