E. N. Plotnikov

Mass spectrometric investigation of the vaporization and thermodynamic properties of components in the BaO-SiO2 system

The vapor composition and thermodynamic properties of components in the BaO-SiO2 system at a temperature of 1970 K are determined using high-temperature mass spectrometry. The thermodynamic properties of melts in the BaO-SiO2 system are calculated within the framework of the vacancy variant of the generalized lattice theory of associated solutions. This made it possible to establish the relation between the thermodynamic properties and the structural features of melts in the BaO-SiO2 system.

Simulation of the thermodynamic properties of glass-forming melts in the Na2O-B2O3-SiO2 system in the framework of the generalized lattice theory of associated solutions

The possibility of calculating the thermodynamic properties of melts in the Na2O-B2O3-SiO2 system (as in the previously studied Cs2O-B2O3-SiO2 system) formed by two glass-former oxides (B2O3, SiO2) and one modifier oxide (Na2O) with the use of the vacancy variant of the generalized lattice theory of associated solutions is demonstrated. A comparison with the experimental thermodynamic functions previously determined by the electromotive force method and high-temperature mass spectrometry at temperatures of 1200, 1273, and 1350 K shows that the calculations performed within this approach lead to reliable thermodynamic functions. It is noted that the proposed model ignores the change in the coordination number of boron atoms to four and the possibility of forming associates in melts of compositions lying in the metastable phase separation region at temperatures higher than the phase separation temperature.

Mass spectrometric investigation of the thermodynamic properties of glass melts in the Cs2O-B2O3-SiO2 system at high temperatures

The composition of the vapor and the activities of cesium metaborate CsBO2 in glass melts of the Cs2O-B2O3-SiO2 system at a temperature of 1020 K are determined using high-temperature mass spectrometry. The activities of the individual oxides Cs2O, B2O3, and SiO2 in glass melts of the Cs2O-B2O3-SiO2 system at a temperature of 1020 K are calculated by the Wagner method from the obtained values of the activities of CsBO2. The integral and excess Gibbs energies are determined.

Thermodynamic properties of melts in the SrO-SiO2 system from data of the generalized lattice theory of associated solutions

The thermodynamic properties of melts in the SrO-SiO2 system are calculated within the framework of the vacancy variant of the generalized lattice theory of associated solutions. It is demonstrated that the results of the calculations are in satisfactory agreement with the experimental data previously obtained using high-temperature differential mass spectrometry of melts in the SrO-SiO2 system.

Calculations of the thermodynamic properties of glasses and melts in the Cs2O-B2O3-SiO2 system in the framework of the generalized lattice theory of associated solutions

The possibility of calculating the thermodynamic properties of glasses and melts in the Cs2O-B2O3-SiO2 system formed by two glass-former oxides and one modifier oxide with the use of the vacancy variant of the generalized lattice theory of associated solutions is demonstrated. A comparison with the experimental thermodynamic functions determined earlier by high-temperature differential mass spectrometry and electromotive force method shows that the calculations performed within this approach lead to reliable thermodynamic functions. The thermodynamic properties and structural features (the relative numbers of bonds with due regard for the second coordination sphere) of glasses and melts in the Cs2O-B2O3-SiO2 system are analyzed in terms of the generalized lattice theory of associated solutions.

Simulation of the thermodynamic properties of glass melts in the Cs2O-B2O3-SiO2 system in the concentration range 0.06–0.50 mole fractions of Cs2O at a temperature of 1020 K

The possibility of calculating the thermodynamic properties of glass melts in the Cs2O-B2O3-SiO2 system with the use of the vacancy variant of the generalized lattice theory of associated solutions is demonstrated. A comparison with the experimental thermodynamic functions previously determined by high-temperature mass spectrometry shows that the calculations performed within this approach lead to reliable thermodynamic functions for glass melts in the Cs2O-B2O3-SiO2 system.