The Corrosion Behaviour of a Pyrazoline Derivative on Mild Steel in Hydrochloric Acid Medium: Electrochemical and Quantum Chemical Investigation

A new pyrazoline derivative, N-methyl-5-(4-methylphenyl)-3-phenyl-4,5-dihydro-1H-pyrazole-1-carbothioamide (MPPC) was synthesized. The corrosion inhibition ability of MPPC for mild steel in 0.5 M HCl was analyzed by electrochemical impedance spectroscopic and potentiodynamic polarization techniques. The corrosion inhibition efficiency of 96% was reported at 50 ppm of MPPC concentration at 303 K. Activation parameters and thermodynamic calculations were performed to understand the corrosion inhibition process by MPPC. The theoretical predictions were executed by density functional theory using Gaussian 16 software. The surface analysis studies were carried out by scanning electron microscopy, EDX, and AFM studies. The experimental results, theoretical calculations, and surface studies confirm MPPC as one of the promising inhibitors for mild steel corrosion.