素材小特集ＩＩＩ ： 素材製造プロセシング アルカリハライド融体の物理化学的性質

Abstract

Physicochemical properties, such as molar volume, surface tension, viscosity and electrical conductivity of alkali halide melts are discussed on the viewpoint of the interaction between the cation and the anion. As the alkali halide melt coheres with long range coulombic force and the physicochemical properties should depend on the radii of the cation and the anion, the systematic study was made on the properties as the functions of the ionic radii. Thermodynamic properties measured almost change according to the order of ionic radius, for example, surface energy increases with decreasing the cationic or anionic radius except lithium halides. It is considered that the phenomena indicate that the cohesive force based on coulombic energy decreases because the short range ionic interaction appears i.e. lithium and sodium ion polarize the anions. In contrast with the thermodynamic properties, transport properties measured do not necessarily show the systematic change with the cationic or anionic radius. It is considered that the transport properties depend on many factors, and the short range interaction plays more important role for transport properties than for the thermodynamic properties.