Stolyarova Valentina L, Vorozhtcov Viktor A, Shemchuk Daria V, Shilov Andrey L, Lopatin Sergey I, Almjashev Vyacheslav I, Shuvaeva Elena B, Kirillova Svetlana A
Institute of Chemistry, Saint Petersburg State University, 7-9 Universitetskaya nab., Saint Petersburg, 199034, Russia.
Laboratory of High Temperature Chemistry of Heterogeneous Processes, Institute of Silicate Chemistry of Russian Academy of Sciences, 2 Nab. Makarova, Saint Petersburg, 199034, Russia.
Rapid Commun Mass Spectrom. 2022 Oct 15;36(19):e9359. doi: 10.1002/rcm.9359.
The TiO -Al O -SiO system is the base for various glass-ceramic materials, which have great practical value for a large number of modern technologies. Many TiO -Al O -SiO materials are synthesized or applied at high temperatures, which justifies the relevance of the present study.
The samples in the TiO -Al O -SiO system were synthesized using the method of induction melting in a cold crucible. The thermodynamic properties of the TiO -Al O -SiO system were studied using the Knudsen effusion mass spectrometric method. The derived thermodynamic functions were optimized within the generalized lattice theory of associated solutions (GLTAS) approach and compared with the results of calculation using the semiempirical Kohler, Muggianu, Toop, Redlich-Kister, and Wilson methods based on the corresponding data in the binary systems.
The SiO selective vaporization from the samples under study was shown at temperatures above 1940 K. The thermodynamic properties in the TiO -Al O -SiO system, including the TiO -SiO system, were obtained in the temperature range 1965-2012 K and were optimized using GLTAS to obtain the consistent concentration dependences of the component activities and excess Gibbs energies.
Positive deviations from the ideal behavior were observed in the TiO -Al O -SiO system at high temperatures. Comparison of these values with the results of the modeling based on the GLTAS approach allowed the recommendations regarding the optimal semiempirical methods for the excess Gibbs energy calculation in different concentration ranges to be made.
TiO₂ - Al₂O₃ - SiO₂体系是各种微晶玻璃材料的基础，这些材料对大量现代技术具有重要的实用价值。许多TiO₂ - Al₂O₃ - SiO₂材料是在高温下合成或应用的，这证明了本研究的相关性。
采用冷坩埚感应熔炼法合成了TiO₂ - Al₂O₃ - SiO₂体系的样品。利用克努森 effusion 质谱法研究了TiO₂ - Al₂O₃ - SiO₂体系的热力学性质。在缔合溶液广义晶格理论（GLTAS）方法内对导出的热力学函数进行了优化，并与基于二元体系相应数据的半经验科勒、穆贾努、图普、雷德利希 - 基斯特和威尔逊方法的计算结果进行了比较。
在高于1940 K的温度下，研究样品中出现了SiO₂的选择性蒸发。在1965 - 2012 K的温度范围内获得了TiO₂ - Al₂O₃ - SiO₂体系（包括TiO₂ - SiO₂体系）的热力学性质，并使用GLTAS进行了优化，以获得组分活度和过量吉布斯自由能的一致浓度依赖性。
在高温下，TiO₂ - Al₂O₃ - SiO₂体系中观察到与理想行为的正偏差。将这些值与基于GLTAS方法的建模结果进行比较，从而能够针对不同浓度范围计算过量吉布斯自由能的最佳半经验方法提出建议。
