A novel L-histidine based ionic liquid (LHIL) was developed and successfully synthesized. Its structure was confirmed by Fourier-transform infrared spectroscopy, UV-vis spectroscopy, X-ray photoelectron spectroscopy, 1H-NMR and high-resolution mass spectrometry. The outstanding corrosion inhibition effect of the LHIL on mild steel in 1 M hydrochloric acid was thoroughly evaluated by Tafel plots, electrochemical impedance spectroscopy, and localized electrochemical strategies. The results revealed that the corrosion of mild steel was effectively suppressed by the adsorption of LHIL on its surface, and the best inhibition efficiency reached 98.8%. The adsorption behavior of LHIL on steel obeyed the Langmuir adsorption isotherm, which involved both chemisorption and physisorption. Theoretical calculations indicated the strong chemisorption of LHIL on steel, as proved by the low energy gap (ΔE = 0.0522 eV) and high binding energy (Ebinding = 303.47 kcal mol−1), which clearly confirmed the effectiveness of LHIL for steel protection.
It is necessary to improve the current efficiency and thickness distribution of the electrodeposition of Al coatings on a Mg alloy from ionic liquids. To accomplish this, finite element method is presented here to help experimental processes to refine various electrodeposition conditions for improving efficiency and economy. However, the simulation of Al deposition from ionic liquids is hindered by the lack of initial parameters in existing works. In this paper, the initial kinetic parameters used in the model were obtained precisely using Tafel plots and cyclic voltammograms. The cathodic and anodic transfer coefficients were calculated to be 0.136 and 0.864 at 318.15 K. The exchange current density for A l 2 C l 7 − / A l C l 4 − redox process was calculated as 4.6A/m 2 at 318.15 K. Subsequently, the multiphysics model in this work combined secondary current distribution, laminar flow, and transport of diluted species. The results of the Al coating thicknesses from finite element method agree well with the experimental method. Hence, the finite element model can precisely predict the Al coating thickness, which provides a positive outlook to analyze the thickness of Al coating and promotes its utilization in industry.