A theoretical model of solid state phase reactions: Hysteresis and kinetics

Hysteresis in the pressure-dependent solid state phase transition Pr₇O₁₂Pr₉O₁₆ is modeled using a thermodynamic formalism. The system is considered to be formed of a fixed number of domains, which are differentiated on the basis of size. The two cases of noninteracting and interacting domains are considered. The interacting domains model allows a better fit to experimental results. In each case, the model is applied to four different isothermal hysteresis curves for the Pr₇O₁₂Pr₉O₁₆ phase transition. The kinetics of the phase transition are studied for the case of noninteracting domains.