Phase diagrams of small particles of binary systems: a theoretical approach

The phase diagrams of small particles (with diameters in the nm range) are studied theoretically. In the limit where thermodynamical arguments remain valid, it is deduced that the phase diagram of small particles is a function of their size. For the case of ideal solutions, it is shown that the lens-shaped solidus-liquidus curves are shifted to lower temperatures when the dimensions of the particle decrease. Additionally, at fixed temperatures between the highest bulk melting point and the lowest melting point of the particle, the relative concentrations of the solid and liquid phases are different in the particle and bulk material.