KINETICS OF SOLIDIFICATION

Abstract

The kinetic theory of melting and freezing is developed from consideration of atom movements at an interface between solid and liquid. The equations developed are shown to have the same form as the corresponding thermodynamic equations. The homogeneous nucleation of a solid phase in a liquid is then considered from the point of view of this theory. Agreement with experimental observation is obtained on the following points. (1) The supercooling at which homogeneous nucleation occurs is proportional to the absolute equilibrium temperature. (2) The surface free energy per atom used in the quasi-thermodynamic treatment of nucleation should be equal to one-half the latent heat per atom. (3) The amount of liquid supercooled has a very small effect on the temperature at which homogeneous nucleation occurs.