(北京化工大学 教育部超重力工程技术研究中心,北京 100029)
摘 要: 在磁力搅拌下,采用离子液体[EMIM]Br-AlCl3作为电解液并测其电导率,在不锈钢片上利用恒电流法电沉积铝,研究在AlCl3/[EMIM]Br摩尔比为2׃1的离子液体中铝的电沉积速率、电流效率和阴极表面形貌的影响因素。采用扫描电子显微镜(SEM)分析沉积铝层的表面形态, 采用X射线能谱仪(EDS)测试沉积铝的纯度。结果表明:离子液体[EMIM]Br-AlCl3的电导率随着温度的上升而增大,符合Arrhenius公式。电流密度,温度、搅拌速率和沉积时间均影响铝的沉积速率、电流效率和表面形貌。在电流密度为20 mA/cm2,温度为40 ℃,搅拌速率为700 r/min,时间为60 min的条件下,所得铝沉积层连续、致密、附着性好、颗粒状且粒径小;电流效率维持在80%以上,阴极铝层纯度达96%,其中少量的氧来自铝的氧化。
关键字: 磁力搅拌;离子液体;恒电流;沉积速率;电流效率
(Research Center of High Gravity Engineering and Technology, Ministry of Education,
Beijing University of Chemical Technology, Beijing 100029, China)
Abstract:In order to investigate the factors of aluminum electrodeposition rate, current efficiency and cathode surface morphology, the [EMIM]Br-AlCl3 ionic liquid was prepared and the conductivity was measured. Alum, inum electrodeposits were conducted on stainless steel from the ionic liquid with AlCl3/[EMIM]Br molar ratio of 2:1 at constant current under magnetic stirring. The quality and purity of the electrodeposition layer were analyzed by SEM and EDS. The results show that the conductivity increases with the temperature increasing, which accords with Arrhenius behavior. Current density, temperature, stirring speed and electrodeposition time are the important factors in aluminum electrodeposition. The aluminum electrodeposits obtained on electrodes is continuous, dense, well adherent and fine particle size under the conditions of current density of 20 mA/cm2, electrodeposition time of 60 min, temperature of 40 ℃ and stirring speed of 700 r/min. The current efficiency is above 80% and the purity of the deposits achieves 96%, where the fraction oxygen is from oxide of aluminum.
Key words: magnetic stirring; ionic liquid; constant current; electrodeposition rate; current efficiency