Suppression of intermediate phase nucleation in binary couples with metastable solubility

This paper investigates the influence of sharp concentration gradients and/or chemical potentials on the nucleation of intermediate phases during solid state reactions between elements with limited solubility. These factors would not appear to have any significant influence on first intermediate phase nucleation. On the other hand, for the second and subsequent phases, thermodynamic suppression (in addition to the kinetic factor) of nucleation can be quite considerable and may well be the reason for sequential phase formation in thin films. Thermodynamic suppression criteria for intermediate phase nucleation are proposed.