超重力场下AlCl_3-BMIC离子液体电沉积铝的电化学

Electrochemistry of electrodepositing aluminum from AlCl_3-BMIC ionic liquid in high gravity field

超重力条件下,温度75℃,以摩尔比为2:1的AlCl3-BMIC离子液体为电解液,在铝电极上采用循环伏安法研究铝的电沉积过程,在不锈钢电极上进行铝的恒电流电沉积实验,并研究超重力环境对铝镀层表面形貌和晶体结构的影响。采用扫描电子显微镜(SEM)和X射线衍射(XRD)分别对铝镀层形貌和晶体结构进行研究。循环伏安实验结果表明,常重力和超重力环境下铝电沉积过程均为扩散控制的准可逆过程,且超重力系数(G)对于电沉积过程中铝离子的扩散系数没有影响;超重力场通过强化电解液中的对流过程而强化电沉积过程。SEM结果表明,超重力场能够细化晶粒、避免枝晶产生,获得附着性良好的镀层。XRD分析表明,铝镀层晶面择优取向为(111)面,并随着G的增大,(111)晶面优势加强。

In high gravity field, the electrodeposition process of Al was studied by cyclic voltammetry （CV） on Al electrodes, and the constant current electrodeposition of Al was conducted on stainless steel electrodes from AlCl3-BMIC ionic liquids with 2：1 molar ratio at 75 ℃. The influence of high gravity field on the surface morphology and crystal structure of the Al coatings was also investigated. Scanning electron microscopy （SEM） and X-ray diffractometry （XRD） were used to study the morphology and crystal structure of the Al coatings, respectively. Analyses of the CV indicate that the electrodeposition of Al is a diffusion-controlled quasi reversible process either in normal or in high gravity field, and the high gravity coefficient （G） has no influence on the diffusion coefficient of Al ions. The electrodeposition process is strengthened with the intensification of convection of electrolyte in high gravity field. SEM results show that high gravity field can refine the grain and avoid dendrite, resulting in good adhesive coatings. XRD analysis reveals that all of the electrodeposits exhibit a preferred （111） crystallographic orientation, and they are enhanced with the increase of G.