Phase diagram reassessment of Ag–Au system including size effect

CALPHAD approach is a very useful technique to reproduce the phase diagram of bulk materials with thermodynamic database such as chemical potentials of pure substances and excess Gibbs energy of mixtures as a function of composition, temperature and pressure. In order to extend the use of CALPHAD approach to small metallic particles on sub-micron and nano scale, due to the surface effect, the chemical potentials and the excess Gibbs energy should be expressed with an additional parameter, viz, the particle size. In this article, a new approach to describe the thermodynamic properties including the size effect is suggested. As a simple example, the chemical potentials and the excess Gibbs energy of Ag–Au system were reassessed as functions of composition, temperature and particle size.