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离子液体中电沉积铝及铝合金的研究
Alternative TitleResearches on electrodeposition of aluminium and aluminium alloy from ionic liquids
张亲亲
Subtype博士
Thesis Advisor张锁江
2014-04
Degree Grantor中国科学院研究生院
Degree Discipline化学工程
Keyword离子液体   电沉积   铝   添加剂   铝锌合金
Abstract铝具有优异的耐蚀性、导电性、导热性及质轻和无毒等特性,是一种理想的钢铁构件防护层。同时,一些合金元素的加入可以提高铝的耐蚀和耐磨等性能,如Al-Ti和Al-Cr合金。铝是一种很活泼的金属,其标准电位为?1.67 V vs. NHE,比氢的还负,几乎不可能从铝盐的水溶液中把铝沉积出来,因而铝及铝合金的电沉积通常在易挥发易燃的有机溶剂和具有强腐蚀性的高温无机熔盐体系中进行。离子液体是近些年来新型的一类介质,具有极低的蒸汽压、较宽的电化学窗口、在室温下呈液体状态、可设计性强等特点,它的出现为铝及铝合金的电沉积开辟了新的道路。铝在离子液体中的电沉积得到了人们的广泛关注,目前存在的问题是,以纯的离子液体为电解质无法兼顾电解质的均镀能力和沉积层的平整性。尽管很多铝合金已被报道可以从离子液体中沉积得到,但关于铝锌合金的报道很少且缺乏系统性。本文从上述背景出发,探索了一系列添加剂对离子液体中铝的电沉积过程的影响,同时系统研究了离子液体中铝锌合金的电沉积。 论文的主要研究内容及成果如下: 1)以烟酰胺为添加剂,以[Bmim]Cl/AlCl3 (40.0/60.0 mol%)离子液体为电解质,通过循环伏安、核磁共振和拉曼光谱测试研究了烟酰胺对Al电沉积过程的影响。同时,系统考察了烟酰胺的浓度、温度和电流密度对Al沉积层的形貌、组成和晶相结构的影响。结果表明,烟酰胺可通过抑制Al的电沉积而起到优异的整平作用,这种抑制作用可能归因于烟酰胺在电极表面的吸附;在适当的烟酰胺浓度、温度和电流密度下,可以沉积得到非常致密平整的纳米晶Al沉积层。 2)以和烟酰胺具有不同取代基位置的两种物质吡啶-4-甲酰胺和吡啶-2-甲酰胺为添加剂,通过循环伏安、核磁共振、拉曼光谱和紫外光谱研究了它们对[Bmim]Cl/AlCl3 (40.0/60.0 mol%)中Al的电沉积过程的影响。同时,在30 °C、?4.0 mA/cm2条件下,考察了两种添加剂的浓度对Al沉积层的形貌、组成和晶相结构的影响。结果表明,吡啶-4-甲酰胺和吡啶-2-甲酰胺对Al电沉积过程的抑制作用弱于等浓度的烟酰胺的作用,这可能归因于它们的微量还原产物在电极表面的吸附。当吡啶-4-甲酰胺和吡啶-2-甲酰胺的浓度增加至32.0 mmol/L时,可沉积得到非常致密平整的纳米晶Al沉积层,它们的平均晶粒大小分别为53 nm和25 nm。 3)以具有烟酰胺某些特征的吡啶、3-哌啶甲酰胺和苯甲酰胺为添加剂,通过循环伏安、核磁共振、拉曼光谱、电导率测试和恒电流电沉积考察了三种物质的浓度对[Bmim]Cl/AlCl3 (40.0/60.0 mol%)中Al沉积层的沉积机理、形貌、组成和晶相结构的影响。结果表明,在考察的浓度范围内,吡啶和3-哌啶甲酰胺的加入均对[Bmim]Cl/AlCl3 (40.0/60.0 mol%)中Al的电沉积过程几乎没有影响,而苯甲酰胺对Al的电沉积产生抑制作用,且该抑制作用随其浓度的增加而增强,不过其作用弱于等浓度的烟酰胺的作用。当苯甲酰胺的浓度为40.0 mmol/L时,在30 °C、?4.0 mA/cm2条件下可沉积得到平均晶粒大小为18 nm的非常致密平整的Al沉积层。 4)以吡啶环3位分别连有吸电子基团和供电子基团的烟酸甲酯和3-羟基吡啶为添加剂,通过循环伏安、核磁共振、拉曼光谱和恒电流电沉积考察了它们对[Bmim]Cl/AlCl3 (40.0/60.0 mol%)中Al沉积层的沉积机理、形貌、组成和晶相结构的影响。结果表明,烟酸甲酯对[Bmim]Cl/AlCl3 (40.0/60.0 mol%)中Al的沉积具有与烟酰胺类似的较强的抑制作用,而相同浓度的3-羟基吡啶对Al的沉积几乎没有影响。在30 °C、?4.0 mA/cm2条件下,加入8.0 mmol/L烟酸甲酯可沉积得到非常致密平整的纳米晶Al沉积层,其平均晶粒大小为13 nm。 5)系统研究了ZnCl2的加入对[Bmim]Cl/AlCl3 (33.3/66.7 mol%)离子液体物种组成和电导率的影响,并通过循环伏安和恒电位沉积考察了此种离子液体中铝和锌发生共沉积的可能性及类型。结果表明,ZnCl2的加入会使得[Bmim]Cl/AlCl3 (33.3/66.7 mol%)中[AlCl4]-的浓度增加,而使[Al2Cl7]-的浓度减小,体系的电导率随ZnCl2添加量的增大而降低,且其随温度的变化符合Arrhenius方程。在含有0.46 wt.% ZnCl2的[Bmim]Cl/AlCl3 (33.3/66.7 mol%)中,锌先于铝开始沉积,没有对应于合金沉积的还原电流出现,所得沉积物中Zn的含量随沉积电位的负移而逐渐降低最后趋于稳定,而在所有考察的沉积电位下所得沉积物均由分离的六方密堆结构的Zn和面心立方结构的Al组成,属于机械混合物合金。
Other AbstractDue to its admirable properties such as excellent corrosion resistance, good electric conductivity and thermal conductivity, low density and non-toxic, Al is an ideal surface coating for various materials, especially for frameworks made of steel. The addition of some alloying elements could imporve the corrosion resisitance and abrasive resistance of Al, such as Al-Ti alloy and Al-Cr alloy. Because of its relatively negative deposition potential, the electrodeposition of Al as well as Al alloys are usually carried out in flammable volatile organic solvents and inorganic molten salts. Due to their unique features such as neglible vapor pressure, wide electrochemical window, being liquids at room temperature and outstanding designability characteristic, ionic liquids are considered as promising media for the electrodeposition of Al and Al alloys. In recent years, electrodeposition of Al and Al alloys has been extensively studied and much progress has been achieved. However, better throwing power and smoother deposits cannot be achieved at the same time using the neat ionic liquids as electrolytes. In addition, there is a paucity of systematic study on the electrodeposition of Al-Zn alloy from ionic liquids. The major research contents and innovative results of this dissertation are listed as follows: 1) The effect of nicotinamide on electrodeposition of Al from the ionic liquid [Bmim]Cl/AlCl3 (40.0/60.0 mol%) was investigated using cyclic voltametry, NMR and Raman spectra. In addition, the effects of nicotinamide concentration, temperature and current density on the morphology, composition and crystal structure of Al depoists were systematically studied. It was indicated that nicotinamide served as a very effective leveling agent through producing an inhibition of Al deposition, which can be attributed to the adsorption of nicotinamide on the electrode surface. Highly uniform and smooth Al deposits with average crystalline size in the nano region can be obtained under appropriate conditions, namely suitable nicotinamide concentration, temperature and current density. 2) The effects of isonicotinamide and picolinamide on the Al deposition process in [Bmim]Cl/AlCl3 (40.0/60.0 mol%) were investigated using cyclic voltametry, NMR, Raman spectra and UV-vis spectra. In addition, the effects of the concentrations of the two additives on the morphology, composition and crystal structure of Al depoists were investigated at 30 °C and ?4.0 mA/cm2. The results showed that both isonicotinamide and picolinamide produced a weaker inhibition of Al deposition than nicotinamide under the same concentration, which is probably due to the adsorption of their trace amounts of reduction products on the electrode surface. Highly uniform and smooth Al deposits with very fine crystallites in the nanometer size regime were obtained with the addition of 32.0 mmol/L additives. The average crystalline size of the deposits obtained with 32.0 mmol/L isonicotinamide and 32.0 mmol/L picolinamide was determined to be 53 and 25 nm, respectively. 3) Pyridine, nipecotamide and benzamide which sharing certain features with nicotinamide were employed as additives to the electrodeposition of Al from [Bmim]Cl/AlCl3 (40.0/60.0 mol%). The effects of their concentrations on the deposition meachanism, morphology, composition and crystal structure of Al deposits were investigated using cyclic voltametry, NMR, Raman spectra and constant current depposition. The results indicated that pyridine and nipecotamide produced no incluences on Al deposition, regardless of their concentrations. Accordingly, the morphology, composition and crystallographic orientation of the obtained Al deposits were similar to that obtained from the neat electrolyte. On the contrary, benzamide produced a weaker inhibition of Al deposition than nicotinamide at the same concentration, but its inhibiting effect could be enhanced with increasing concentration. Highly uniform and smooth A
Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/15548
Collection研究所(批量导入)
Recommended Citation
GB/T 7714
张亲亲. 离子液体中电沉积铝及铝合金的研究[D]. 中国科学院研究生院,2014.
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