Part Ii: Impact Of Ionic Liquids As Anticorrosives And Additives On Ni-Co Alloy Electrodeposition: Experimental And Dft Study

The impacts of 1-methyl-3-(2-oxo-2 ((2,4,5trifluorophenyeamino)ethyle)-1H-imidazol-3ium iodide ([MOFIM]I) and 1-(4-fluorobenzyl)-3-(4-phenoxybutyl)imidazol-3-ium bromide ([FPIM]Br) ionic liquids as additives on the corrosion behavior and the electrodeposition nucleation mechanism of a Ni-Co alloy were elucidated. A systematic investigation of the corrosion protection ability of Ni-Co alloys in a 3.5% NaCl solution was carried out using Tafel polarization and electrochemical impedance spectroscopy (EIS) studies. The mechanism of the Ni-Co alloy electrodeposition from the Ni70-Co30 bath was investigated using potentiodynamic cathodic polarization, cyclic voltammetry (CV) and anodic linear stripping voltammetry (ALSV). The studied ionic liquids (ILs) inhibit Co2+ and Ni2- ion deposition due to their adsorption, which obeys the Langmuir adsorption isotherm. Quantum chemical calculations were performed at the B3LYP/6-311 + + G(d,p) level of the density functional theory (DFT). Several quantum parameters and natural atomic charges were calculated to investigate the correlation between the molecular structures of [MOFIM]I and [FPIM]Br and their corrosion inhibition performance. [MOFIM]I at 1 x 10(-5) M shows a higher inhibition efficiency (IE%) of 53.05% than [FPIM]Br, at 44.3%. The results show that the calculated values of the quantum parameters are consistent with the experimental findings. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.