Enhanced corrosion inhibitive effect of p-methoxybenzylidene-4,4′-dimorpholine assembled on nickel oxide nanoparticles for mild steel in acid medium

Abstract

The corrosion inhibition efficiency of p-methoxybenzylidene-4,4′-dimorpholine (p-MBDM) and p-MBDM assembled on nickel oxide nanoparticles (NiONPs) was investigated using three techniques: weight loss, electrochemical impedance spectroscopy (EIS), and galvanostatic polarization. For the first time, p-MBDM and p-MBDM assembled on NiONPs were used as efficient inhibitors for mild steel (MS) in 2 M hydrochloric acid (HCl) solution. From weight loss measurements, the results show that the inhibition efficiency increases with an increase in inhibitor concentration. Moreover, with increasing temperature, the inhibition efficiency increases for p-MBDM assembled on NiONPs, whereas it decreases for p-MBDM only. EIS spectra demonstrate that the charge transfer resistance in the case of p-MBDM assembled on NiONPs is comparatively more than that of p-MBDM. Analysis of polarization data indicates that both inhibitors act as mixed type inhibitors. The present study reveals that p-MBDM assembled on NiONPs is more efficient than p-MBDM alone. Additionally, the characterization of synthesized products was performed by proton nuclear magnetic resonance (¹H NMR), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), and electrospray ionisation mass spectrometry (ESI-MS). The surface morphology of the MS was further carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM).