A study of synthesized Mannich base inhibition on mild steel corrosion in acid medium

1((Cyclohexylamino)methyl)urea Mannich base was synthesized and characterized using FT-IR, H¹NMR and C¹³NMR spectra and it was tested as a corrosion inhibitor for mild steel in 1?N HCl and 1?N H₂SO₄ solutions using potentiodynamic polarization and AC impedance techniques over the temperature range of 303?C333?K. The inhibition efficiency was increased with respect to concentration of inhibitor and temperature in 1?N HCl, whereas the inhibition efficiency was increased with respect to concentration of inhibitor and decreased with respect to temperature in 1?N H₂SO₄. Potentiodynamic polarization results revealed that the inhibitor acts as mixed type inhibitor. AC impedance study indicates that the corrosion of steel was mainly controlled by a charge transfer process. Surface analysis was carried out using SEM technique. The adsorption of inhibitor follows Langmuir adsorption isotherm. Activation and adsorption parameters were calculated to gain information about the inhibitive action mechanism.