The numbers of critical nuclei and embryos for coherent precipitation of a new phase of different composition

Abstract The increase in free energy which accompanies homogeneous nucleation, the number of atoms contained in the critical nucleus and the concentration of nuclei formed during coherent continuous precipitation in a dilute regular solution, as well as their temperature dependences, are discussed on the basis of a statistical-thermodynamic approach. A theoretical equation describing the relationship between the concentration of small atom groups and the change in configurational entropy is proposed and developed, so as to evaluate the numbers of nuclei and embryos with equilibrium size distribution, by introducing the enthalpy change due to the decrease in the number of atomic bonds between unlike atom.