Thermodynamic reassessment of the La-Mn system

The binary La-Mn system is investigated by CALPHAD approach. The experimental phase diagram and thermodynamic data available in the literature are critically reviewed and assessed using the thermodynamic models for the Gibbs energies of individual phases. A set of consistent thermodynamic data for the La-Mn system is obtained by optimization of the selected experimental data. The miscibility gap is no more existent in the optimized phase diagram. The calculated phase diagram agrees well with the experimental data.

Thermodynamic assessment of the MgO–Al2O3–SiO2 system

Thermodynamic properties of the phases in the MgO–Al2O3–SiO2 system were assessed, resulting in a set of self-consistent thermodynamic data. The two ternary compounds, cordierite and sapphirine, were optimized from subsolidus reactions. The liquid phase was described by the ionic two-sublattice model with a new species AlO2−1, yielding the formula (Al+3,Mg+2)P(AlO2−1,O−2,SiO4−4,SiO20)Q. Projection of the liquidus surface was calculated. Various isothermal and isoplethal sections were compared with the experimental data.

Thermodynamic characterization of high-temperature superconductors in the yttrium-barium-copper-oxygen system. The Y123 solid solution (Technical Report)

The aim of this report is to inform the chemical community about a self-consistent thermodynamic data set for the YBa2 Cu3 O6+z (1 ≥ z ≥ 0) solid solution, that is well known as the Y123 phase and possesses superconducting properties at z~1 and low temperatures. About 3300 experimental points obtained in 240 miscellaneous experiments published in 78 papers have been processed simultaneously in order to obtain the most reliable Gibbs energy function of the Y123 phase in the temperature range from 250 to 1300 K and pressures up to 100 kbar. A function is recommended for approximation of the Gibbs energy, which has 16 adjustable parameters. All other thermodynamic properties of the Y123 solution, including the conditions for its internal stability, can be derived from the assessed Gibbs energy. Brief descriptions of the thermodynamic model, experimental and data assessment methods as well as examples of self-consistent thermodynamic data applications are given.