Self-Diffusion in Solid Sodium. II. The Effect of Pressure

Abstract

Hydrostatic pressure is found to decrease the rate of self-diffusion in sodium. The free energy of activation is a linear function of the melting point, and the enthalpy of activation is proportional to the melting point. For sodium and for all cubic metals (except lead and tungsten) for which diffusion data exist the enthalpy of activation is related to the latent heat of fusion by the equation ΔH = 16.5 Lm. The change in D0 for sodium with pressure is expressible in terms of the compressibility and the activation entropy change.