Impact of novel ZnO/PAA nanocomposite as corrosion inhibitor on mild steel in 5% HCl

Zinc oxide nanoparticles (ZnO NPs) were synthesized by co-precipitation method and characterized through ultraviolet (UV–Vis), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) spectroscopy. The corrosion inhibition of mild steel in 5% hydrochloric acid (HCl) by ZnO NPs, Polyacrylamide (PAA) and Zinc oxide/polyacrylamide (ZnO/PAA) nanocomposite was investigated by gravimetric and electrochemical methods. This work aimed to develop a novel nanocomposite using in-situ polymerization depending on NPs and PAA to evaluate its inhibitive properties towards surface of mild steel in corrosive medium of 5% HCl. The nanocomposite exceeded 33% inhibition efficiency over ZnO NPs (62.76%) and PAA (76.59%), respectively. As investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements and weight loss method, mixed type of inhibition mechanism and Langmuir adsorption isotherm were followed by all three inhibitors. Results of surface analysis and thickness of deposited layer by Atomic force microscopy (AFM) and Optical Microscope respectively agreed with other experimental outputs.