Electrochemical Nucleation and Growth Mechanism of Aluminum on AZ31 Magnesium Alloys

Abstract

In this study, the nucleation and growth kinetics behavior of aluminum (Al) were investigated in the Choline-chloride (ChCl)-urea deep eutectic solvent (DES) ionic liquids. The studies of cyclic voltammetric and chronoamperometry demonstrated that the electrodeposition process of Al was controlled by three-dimensional progressive nucleation and instantaneous nucleation. And the growth of nuclei is a diffusion-controlled process. The diffusion coefficient of Al ions was calculated at 343 K, that is, 1.773 × 10−10 cm2/s. The Al coating was obtained on the surface of the AZ31 magnesium alloy electrode under appropriate conditions. According to the surface morphology of the Al film, it could be inferred that the theoretical deposit thickness is similar to the actual thickness, and the apparent diffusion rate of Al ions is slower than the diffusion coefficient in the electrolytes. So, in the later deposition, lamellar Al along the diffusion direction were formed, and lamellar depleted Al zones existed around the big grain Al-rich region.

Design Strategy and Application of Deep Eutectic Solvents for Green Synthesis of Nanomaterials

“…Cvetkovic and coworkers have shown that using DES to control the electrodeposition of aluminum (Al) with Al grains varied in size from nano- to micro-meters [ 149 ]. The usage of DES-based ChCl-U for the electrodeposition of aluminum was addressed [ 150 , 151 ]. The nucleation and growth of Al were studied in ChCl-U [ 151 ].…”

“…The usage of DES-based ChCl-U for the electrodeposition of aluminum was addressed [ 150 , 151 ]. The nucleation and growth of Al were studied in ChCl-U [ 151 ]. In another work, gold and silver were recycled from anodic slime using choline chloride and ethylene glycol (molar ratio of 1:2) [ 152 ].…”

Design and Fabrication of a Sandwichlike Zn/Cu/Al–Zr Coating for Superior Anticorrosive Protection Performance of ZM5 Mg Alloy

“…Zhang et al . demonstrated the nucleation and growth mechanism of Al in the ChCl–urea deep eutectic solvent ionic liquid . Xu et al investigated the anodic behavior of Mg in the acidic AlCl 3 –EMIC ionic liquid .…”

“…Zhang et al demonstrated the nucleation and growth mechanism of Al in the ChCl−urea deep eutectic solvent ionic liquid. 13 Xu et al investigated the anodic behavior of Mg in the acidic AlCl 3 − EMIC ionic liquid. 14 Tang et al performed zinc (Zn) immersion pretreatment for the AZ91D Mg alloy with the bipolar current pulse technique to increase the bonding force and anticorrosion ability of the Al coating.…”