AlCl_3-NaCl-KCl熔融盐中铝的电沉积  

Electrodeposition of aluminum from AlCl_3-NaCl-KCl molten salt

作　　者：李景升[1] 杨占红[2] 王小花[2] 李旺兴[3] 陈建华[3] 王升威[2] 李景威[2] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083 [2]中南大学化学化工学院,湖南长沙410083 [3]中国铝业公司郑州研究院,河南郑州450041

出　　处：《中南大学学报（自然科学版）》2008年第4期672-676,共5页Journal of Central South University:Science and Technology

基　　金：国家科技支撑项目(2006BAE03B03)

摘　　要：在摩尔比为0.66:0.17:0.17的AlCl3-NaCl-KCl共融盐中,控制阴极电流密度在基体铁片上获得银白色铝镀层。用扫描电镜、X射线物相分析对所得镀层进行显微组织分析,并用循环伏安法研究熔融盐中铝沉积的机理。研究结果表明:当电流密度为25mA/cm2时,所得铝晶粒为针状,以(200)面构成为主;当电流密度为40mA/cm2时,最大电流效率达到92%;当电流密度超过80mA/cm2时,电流效率随电流密度的增大急剧减小;当电流密度增至60mA/cm2时,所得晶粒既有针状也有球形,以(111)面构成为主;当电流密度为100mA/cm2时,所得铝晶粒呈球形;所得铝镀层厚度与电镀时间呈抛物线关系,与电流密度呈直线关系;熔融盐中沉积铝源于Al2Cl7?的还原,还原峰电位为-0.23V。Silvery bright aluminum coating was obtained on iron substrate from 0.66：0.17：0.17（mole ratio） AlCl3-NaCl-KCl molten salt at various cathode current densities. The microstructure of the coating was investigated by SEM and XRD, and the mechanism of electrodeposition was illuminated by cyclic voltammogram. The results show that when cathode current density is 25 mA/cm^2, aluminum coating is acicular and （200） plane structure is reliable to be formed. The maximal current efficiency of 92% is obtained when current density is 40 mA/cm^2 and it decreases sharply after current density is over 80 mA/cm^2. When cathode current density is 60 mA/cm^2, the obtained aluminum crystalline grain is a mixture of acicular and spherical, aluminum coating has （111） cubic structure. When current density is 100 mA/cm^2, spherical aluminum coating is reliable to be formed. The thickness of aluminum coating increases with prolongation of plating time and the increase of cathode current density. The deposition is obtained owing to the reduction of Al2Cl7 which has a peak value of-0.23 V.

关 键 词：熔融盐 铝 表面形貌 相结构 镀厚 电沉积 

分 类 号：TQ153.2[化学工程—电化学工业]