Abstract:

The freezing point is an important thermodynamic parameter to represent the solid-liquid phase change process. Experiments showed that electrostatic field can change the solid-liquid equilibrium, thus, it is a method of regulating the solid-liquid phase transition process. In this paper, based on the principle of phase equilibrium, and employing the expression of chemical potential under the action of electrostatic field, a mathematical expression for freezing point with the influence of electrostatic field was derived. The characteristics of the change in freezing point with electrostatic field was investigated through numerical calculations, which showed that the change is proportional to the square of the electric field strength, and the change is also related to the physical properties of the material. According to the difference in dielectric constants between solid phase and liquid phase, the freezing point of some substances increases and others decrease under the action of electrostatic field.

Key words: phase change, phase equilibria, freezing point, thermodynamic properties

摘要：

凝固点是表示固液相变过程的重要热力学参量。实验表明，静电场能够改变固相、液相平衡，是一种调控固液相变过程的手段。基于相平衡理论，利用电场作用下的化学势，导出了静电场作用下液体凝固点的数学表达式。通过数值计算，分析了凝固点随静电场变化的规律。理论推导和实例计算都表明，凝固点的变化量与电场强度的平方成正比，变化量还与物质的物性参数有关。依据固体和液体介电常数的差别，静电场作用下，有些物质的凝固点升高，有些物质凝固点降低。

关键词: 相变, 相平衡, 凝固点, 热力学性质