High‐temperature mass spectrometric study of the vaporization processes and thermodynamic properties in the Gd₂O₃‐Y₂O₃‐HfO₂ system

Abstract

The thermodynamic properties of the Gd O -Y O -HfO system, i.e., the component activities in the samples and the excess Gibbs energy, obtained in the present study at 2500 K, exhibited negative deviations from ideal behavior. The concentration dependence of excess Gibbs energy of the Gd O -Y O -HfO system was approximated with an empirical equation. Copyright © 2017 John Wiley & Sons, Ltd.

Vaporization and thermodynamics of ceramics based on the La2O3‐Y2O3‐HfO2 system studied by the high‐temperature mass spectrometric method

“…The vaporization processes and thermodynamic properties of the samples in the La 2 O 3 ‐Y 2 O 3 ‐HfO 2 system were studied with a MS‐1301 mass spectrometer (Institute for Analytical Instrumentation of the Academy of Sciences of USSR, Saint Petersburg, Russia) . In the present study, as was repeatedly done earlier, a molecular beam for the mass spectrometric analysis was formed using a tungsten twin Knudsen effusion cell heated by electron bombardment. In the experiments the samples were placed in one compartment of the effusion cell and another compartment of the effusion cell was loaded with a reference substance (pure La 2 O 3 or Y 2 O 3 ).…”

“…The sample synthesis was carried out by the conventional solid‐state method using the technique employed in our previous study . The required blends of oxides were pressed into pellets under 200 bar pressure, heated to 1973 K for 6 h and held at the maximum temperature for 1 h. In contrast to the approach of Kablov et al in the present study the sample pellets were allowed to cool and then ground to fine powders.…”

“…The sample synthesis was carried out by the conventional solid‐state method using the technique employed in our previous study . The required blends of oxides were pressed into pellets under 200 bar pressure, heated to 1973 K for 6 h and held at the maximum temperature for 1 h. In contrast to the approach of Kablov et al in the present study the sample pellets were allowed to cool and then ground to fine powders. The synthesis procedure was then repeated: the powders were pressed into pellets under of 200 bar pressure, again heated up to 1973 K for 6 h with isothermal holding at the maximum temperature for 1 h. The samples were allowed to cool in the switched off furnace.…”

“…Studies of systems containing hafnia and rare earth oxides showed that the vapor over the samples in these systems contains the same species as those over the pure oxides constituting these systems . Let us consider the available information on vaporization processes of pure oxides in the La 2 O 3 ‐Y 2 O 3 ‐HfO 2 system.…”

Thermodynamic properties of gaseous BaSnO2 and Ba2O2 studied by Knudsen effusion mass spectrometry

“…The experiments were carried out by the Knudsen effusion method combined with mass spectrometric analysis of the vapor, as described in detail elsewhere, using a MS 1301 magnetic sector mass spectrometer (Construction Bureau, Academy of Science, St. Petersburg, Russian Federation). Ionization of the vapor species was performed by electron ionization, with the energy of ionizing electrons being 25 eV and with 3 kV accelerating voltage.…”