Transition of a binary solution into an inhomogeneous phase

TL;DR

This paper theoretically investigates the phase transitions of binary solutions into inhomogeneous states, revealing a two-stage process involving phase stratification and a second-order transition to concentration waves, with thermodynamic properties analyzed.

Contribution

It introduces a theoretical model accounting for nonlinear effects in phase transitions, detailing the transition sequence and thermodynamic contributions in binary solutions.

Findings

Phase stratification occurs below the spinodal temperature.

A second-order transition to concentration waves follows stratification.

Inhomogeneity affects entropy and heat capacity of phases.

Abstract

The thermodynamics of phase transitions of binary solutions into spatially inhomogeneous one-dimensional states is studied theoretically with taking into account nonlinear effects. It is shown that below the spinodal decomposition temperature there first occurs a phase stratification, and at a lower temperature, after reaching the maximum possible stratification, there occurs a second-order transition into the phase with concentration waves. The contribution of inhomogeneity to the entropy and heat capacity of phases is calculated and the phase diagram in the coordinates temperature and average concentration is constructed.