Surface stress and the chemical equilibrium of small crystals—I. the case of the isotropic surface

Abstract The equilibria of small solid solution crystals with isotropic surfaces in contact with vapor or fluid solutions is considered when the surface stress differs numerically from the surface free energy. The interstitial components of the solid are shown to have a constant chemical potential throughout the system, while the chemical potentials of the substitutional components are not constant unless the magnitude of the surface stress equals the surface free energy. Six examples are given to illustrate various equilibria. Only the surface stress acts on the interstitial component, while the substitutional components are affected by the surface free energy and in most circumstances by the surface stress as well.