熔盐电解制备铝钕中间合金及其机理

Preparation for Al-Nd intermediate alloy by molten-salt electrolysis method and its mechanism

以Na_3AlF_6-AlF_3-MgF_2-LiF为电解质,Al_2O_3、Nd_2O_3为原料,对熔盐电解制备Al-Nd中间合金进行研究;采用扫描电子显微镜(SEM)、能谱(EDS)分析合金产物的形貌及组成;通过还原实验和循环伏安法,对Nd(Ⅲ)离子在Na_3AlF_6-AlF_3-MgF_2-LiF体系中的还原过程进行表征。结果表明:在温度935℃、恒压3.2 V条件下,通过Na_3AlF_6-AlF_3-MgF_2-LiF-(Al_2O_3、Nd_2O_3)体系可电解得到Al-Nd中间合金,富钕相集中分布在铝基体晶界区域,Nd(Ⅲ)离子主要通过铝热还原形式进入合金相,且Nd_2O_3的加入可起到去极化作用,使Al(Ⅲ)离子扩散系数大幅提高。

Preparation of Al-Nd intermediate alloy was studied in the system using Na3AlF6-AlF3-MgF2-LiF as electrolyte and Al2O3,Nd2O3 as raw materials.The morphology and composition were analyzed by scanning electron microscope（SEM） and energy spectrum（EDS）.The reduction process of Nd（Ⅲ） ion in Na3AlF6-AlF3-MgF2-LiF system was characterized by reduction experiment and cyclic voltammetry.The results show that Al-Nd intermediate alloy can be obtained by electrowinning in Na3AlF6-AlF3-MgF2-LiF-（Al2O3,Nd2O3） system at the temperature of 935℃ and constant voltage of 3.2 V.Neodymium-rich phase of alloy samples distributes in the region of aluminum grain boundary.The form of Nd doping into the alloy phase is mainly used by aluminothermic reduction.The effect of Nd2O3 is depolarization and makes the Al（Ⅲ） ion diffusion coefficient increase significantly.