Critical evaluation and thermodynamic optimization of the VO–VO2.5 system

A critical evaluation, and thermodynamic optimization of phase equilibrium and thermodynamic properties of the VO–VO2.5 system are presented. Optimized model parameters for all the oxide phases were obtained so as to reproduce all available and reliable experimental data within experimental error limits. Liquid oxide phase was modeled using the modified quasichemical model in the pair approximation with components representing various valences of vanadium (VO, VO1.5, VO2, and VO2.5) in the liquid oxide. Solid VO and V2O3 phases were modeled using simple random mixing models, while all other solid phases were assumed to be stoichiometric compounds. Type of defects in the V2O3 solid solution was shown to be extended cluster type defect, based on the available experimental data. Using the presently optimized model parameters, most experimental data has been well reproduced, therefore, the present work can be further extended for the development of thermodynamic database for V oxide containing system.