Gibbs–Schreinemakers–Meijering Mechanisms for 3-Phase Miscibility Gap Formation

Abstract

A review is given of work by J.W. Gibbs, F.A.H. Schreinemakers and J.L. Meijering on the stability of solutions to a continuous change in a phase. Gibbs laid the theoretical foundation with mathematical equations for multicomponent systems written in terms of the Gibbs energy. Later, Schreinemakers and Meijering predicted mechanisms by which 3-phase miscibility gaps could form in a ternary system. Their mechanisms were described in a series of phase diagram sketches, but the mechanisms have not yet been confirmed by experiment or calculation. In this work, phase diagrams were calculated using regular and subregular solution models and compared with the sketches. Several sketches contained unusual features like multiple critical points that form spontaneously at a single composition. In one mechanism a miscibility gap forms spontaneously in the metastable supersaturated phase of an existing miscibility gap. The calculated diagrams show from a thermodynamic standpoint that Schreinemakers’ and Meijering’s mechanisms can occur. However, there is no experimental evidence that they have occurred.