间歇式电解制备高活性LaNi5-xAlx合金薄膜的研究

Study on preparation of highly active LaNi5-xAlx alloy films using pulse electrolysis

摘要:

通过间歇式熔盐电解技术制备一种高活性LaNi5-xAlx合金薄膜材料，采用热力学计算、循环伏安技术研究Ni阴极的去极化能力以及在氧化物熔盐电解体系中La、Al的共析出条件，采用扫描电镜和X射线衍射仪对合金薄膜材料表层的显微组织结构进行观察与分析。结果表明：采用间歇式脉冲电解可以将电沉积和扩散过程有效分离，在设计Na3AlF6114g、Al2O31.2g以及La2O34.8g的熔盐体系中Ni阴极上首先析出Al，形成液态Al-Ni阴极，使稀土La2O3活度大大降低，发生去极化作用，实现La、Al共析出，进而制备出高活性、成分均匀的LaNi5-xAlx合金薄膜，其中X的值介于3.5-4之间。

Abstract:

A highly active LaNi5-xAlx alloy films was prepared by using pulse electrolysis. The depolarization of Ni cathode and the co-electrodepositing principle in the molten salt system was studied by thermodynamic calculation and cyclic voltammetry, microscopic structures of alloy films were observed and analyzed by scanning electron microscopy and X-ray diffractometry. The results show the electrodeposition and diffusion processes are effectively separated by pulse electrolysis. In fact, the precipitation of aluminium in Ni cathode is found to significantly decrease the activity of La2O3 from Na3AlF6114g, Al2O31.2g and La2O34.8g molten salts firstly, then the depolarization of Ni cathode makes it possible for the co-electrodepositing principle of La and Al. Finally, the LaNi5-xAlx alloy films with high surface area and uniform composition is prepared, where x values rang between 3.5-4.