Experimental Evaluation of Inter facial Segregation between Liquid Alloys and Molten Salt by using Electro-chemical Capillarity

虽然从热力学的角度认识到液态合金与熔盐之间的界面偏析，但用任何实验方法都不能直接看到这一现象。这种分离发生在几个原子层内。由于电化学毛细效应对上述极小原子区的物理化学性质的变化非常敏感，因此可以利用电化学毛细效应来检测界面的偏析。在本工作中，我们制作了电化学毛细管实验装置，并通过测量液态合金与熔盐之间的界面超额电荷来证实上述两液相之间的界面偏析。首先，测量了不同铋组分的熔融LiCl-KCl体系和液态Ga-Bi合金的毛细管电化学曲线。在此基础上，得到了液态Ga-Bi合金中界面过剩电荷与体相组成之间的关系，这与液态Ga-Bi合金中表面偏析与体相成分之间的关系相对应。因此，从上述实验中可以发现，可以通过测量电化学毛细管来评价液态合金与熔盐之间的界面偏析。

Although the interfacial segregation between liquid alloys and molten salt is recognized from a thermodynamic view point, the phenomenon can not be seen directly by using any experimental method. This segregation occurs within a few atomic layers. Since the electro-chemical capillarity is quite sensitive to the change of the physico-chemical properties in the above very small atomic region, the interfacial segregation might be detected by using the electro-chemical capillarity. In the present work, the experimental apparatus for the electro-chemical capillarity was made, and then the interfacial excess electric charge between liquid alloys and molten salt was measured to confirm the above interfacial segregation between these two liquid phases. First of all, the electro-chemical capillary curves were measured for molten LiCl-KCl systems and liquid Ga-Bi alloys, of which compositions of Bi were changed. Then, the relationship between the interfacial excess electric charge and the bulk composition of Bi in liquid Ga-Bi alloys was obtained, which corresponded to the relation between the surface segregation and the bulk composition of Bi in liquid Ga-Bi alloys. Thus, it was found from the above experiments that the interfacial segregation between liquid alloys and molten salt can be evaluated from the measurement of the electro-chemical capillarity.