AlCl3/urea类离子液体电沉积铝

类离子液体是近年发展起来的一种新型溶剂，它不仅具有离子液体独特的物理化学性能，还具有合成简单、价格低廉等优点，在电沉积铝技术方面具有广阔的应用前景。但目前相关的作用机制还未明确，而这些对于开发类离子液体电解生产铝和电解精炼铝的新工艺又至关重要。因此，本文以三氯化铝/尿素(AlCl3/urea)类离子液体为电解质，利用电导率仪、黏度计、线性扫描伏安法、场发射电子扫描显微镜(FE-SEM)和X射线衍射仪(XRD)等测试手段研究了AlCl3/urea类离子液体的物理化学性质、铝在电解质中的电化学行为以及铝沉积产物的形貌和物相结构。系统分析AlCl3/urea摩尔比和温度对体系电导率和黏度的影响，研究温度对铝离子析出电位、铝离子还原反应过程动力学、沉积铝形貌和结构的影响规律。结果表明，相同条件下，摩尔比为1.3:1的AlCl3/urea电解质电导率最大，黏度最小，物理化学性质较为优良，且其电导活化能为19.82kJ·mol-1。研究发现升温促进了电荷迁移反应，使得金属铝的析出电位正移，交换电流密度增大，说明较高的温度有利于加快Al(III)离子在铜基体上的还原。FE-SEM结果表明温度的变化对铝沉积产物的表观形貌影响不大，均由不规则的微米块体组成，但对粒径和致密性有一定影响。XRD结果分析表明晶粒的生长方式也受到了温度的影响，但都具有(111)晶面优先取向。

Electrodeposition of Aluminum Using AlCl3/urea Ionic Liquid Analogues

Ionic liquid analogues are new solvents developed in recent years, which not only have the unique physicochemical properties of ionic liquids, but also have the advantages of simple synthesis and low price, offering great prospects for application in electrodeposition aluminum technology. However, the relevant mechanisms remain to be clarified, and these in turn are crucial for the development of new processes for the ionic liquid analogues electrolytic refining of aluminum. In the present work, the physicochemical properties of AlCl3/urea ionic liquid analogues, electrochemical behaviors of aluminum in the electrolyte, the morphology and phase structure of the deposited aluminum were investigated using such tests as conductivity meter, viscometer, linear sweep voltammetry, field emission scanning electron microscope (FE-SEM) and X-ray diffractometer (XRD). The effects of AlCl3/urea molar ratio and temperature on electrical conductivity and viscosity were systematically analyzed. The effects of temperature on the precipitation potential of aluminum ion, the kinetics of the reduction process of aluminum ion, the morphology and structure of the deposited aluminum were investigated. The results showed that the AlCl3/urea electrolyte with a molar ratio of 1.3:1 had better physicochemical properties because of the highest conductivity and the lowest viscosity under the same conditions, and its conductive activation energy was 19.82 kJ·mol-1. It was found that the increase in temperature promoted the charge migration reaction, resulting in a positive shift in the precipitation potential of aluminum and an increase in the exchange current density. This trend was reinforced by the increase in temperature, indicating that the higher temperature facilitated the faster reduction of Al(III) ions on the copper substrate. FE-SEM results showed that changes in temperature had little effect on the apparent morphology of aluminum deposition products, but had some influence on particle size and denseness. XRD analysis indicated that the grain growth pattern was also influenced by temperature, but all with (111) preferential orientation of the crystal plane.