Time Lag in Heterogeneous Nucleation due to Nonstationary Effects

Abstract

The basic expression for the time lag in nonstationary nucleation in a homogeneous medium is discussed in some detail. Since heterogeneous nucleation is dominant in phase transitions, formulas may be developed to account for the influence of the substrate on the time necessary to establish a stationary nucleation rate. The following models are considered: isotropic nuclei on a solid substrate, crystalline nuclei on a solid substrate and isotropic nuclei growing by surface diffusion of components previously adsorbed onto the substrate. The analysis shows that the time lag is usually smaller than that of the homogeneous case under the same conditions.