S. I. Lopatin

Phase equilibria and thermodynamic properties of components in the Cs2O-B2O3-SiO2 system at high temperatures

The phase equilibria in the Cs2O-B2O3-SiO2 system are investigated in the temperature range 873–1073 K by the annealing-quenching technique, high-temperature microscopy, and X-ray powder diffraction analysis. The vapor composition, the activities of the components, and the Gibbs energies of glasses and melts in the Cs2O-B2O3-SiO2 system are determined at a temperature of 1020 K. It is demonstrated that glasses and melts in the Cs2O · B2O3-Cs2O · SiO2 system are characterized by positive deviations of the CsBO2 activities and negative deviations of the Cs2O · SiO2 activities from ideal behavior. As a consequence, the deviations of the Gibbs energies from ideal behavior change their sign.

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.

Thermodynamic properties and structure of gaseous metaborates

A review is presented of the data available in the literature on the thermodynamic properties and structure of gaseous metaborates studied by high-temperature mass spectrometry, gas-phase electron diffraction, spectroscopy, and quantum-chemical methods. The reliability and inconsistency of the thermodynamic properties and structural data obtained by these methods for gaseous metaborates are discussed. The specific features of the application of the above methods for investigating the thermodynamic properties and structure of gaseous metaborates at high temperatures are analyzed.

Mass Spectrometric Study of the Thermodynamic Properties of Melts in the Rb2O–B2O3 System

The vaporization and thermodynamic properties (activities of the components and Gibbs energies) of melts in the Rb2O–B2O3 system at a B2O3 content varying from 66.7 to 92.0 mol % are investigated by high-temperature differential mass spectrometry upon evaporation from molybdenum cells in the temperature range 950–1350 K.

Determination of the SiO2 Activity in Melts of the CaO–Al2O3–SiO2 System by High-Temperature Mass Spectrometry

This paper reports on the results of systematic investigations into the thermodynamic properties of melts lying along the joins with constant SiO2 contents of 0.5 and 0.6 mole fractions in the CaO–Al2O3–SiO2 system at mole fraction ratios CaO : Al2O3 varying from 0.25 to 4.0. The activities of SiO2 in melts of this system at a temperature of 1905 ± 10 K are determined by high-temperature mass spectrometry. It is found that, in the concentration range studied, the activity of SiO2 remains constant at SiO2 contents of 0.5 and 0.6 mole fractions.

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.