In Honor of Nobel Laureate Prof. M Stanley Whittingham
| EXPERIMENTAL INVESTIGATION OF THERMODYNAMIC PROPERTIES OF RARE-EARTH HAFNATES Alexandra Khvan1; Irina Bajenova2; Anton V. Guskov3; Pavel G. Gagarin3; Vladimir N. Guskov3; Konstantin S. Gavrichev3; 1NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY, Moscow, Russian Federation; 2LABORATORY OF CHEMICAL THERMODYNAMICS, FACULTY OF CHEMISTRY, LOMONOSOV MOSCOW STATE UNIVERSITY, Moscow, Russian Federation; 3KURNAKOV INSTITUTE OF GENERAL AND INORGANIC CHEMISTRY OF RAS, Moscow, Russian Federation; PAPER: 122/Geochemistry/Regular (Oral) OS SCHEDULED: 16:20/Wed. 29 Nov. 2023/Coral Reef ABSTRACT: Ceramic materials based on the RE2O3-HfO2 system are interesting from the standpoint of the development of advanced materials for TBCs. This is due to high strength characteristics, low thermal conductivity and high melting temperatures [1,2]. Yet the data on the thermodynamic properties for the compounds with the pyrochlore structure is quite limited. Thermodynamic properties of pyrochlore compounds RE2Hf2O7 (where RE = La, Pr, Nd – Tb) and solid solutions RE2O3·HfO2 (RE=Dy-Lu) were determined in the temperature range between 2 and 1800 K using relaxation and adiabatic calorimetry and DSC methods. Enthalpies of formation of RE hafnates were determined by high-temperature oxide melt drop-solution calorimetry. The obtained results have been compared with the data for titanates and zirconates and have shown the similar dependence of the formation enthalpy from the ionic radii of the rare-earths. AKNOWLEDGEMENTS: The study was supported by Russian Science Foundation project № 18-13-00025. References: [1] Liu B., Liu Y.C., Zhu C.H., Xiang H.M., Chen H.F., Sun L.C., Gao Y.F., Zhou Y.C., J. Mater. Sci. Technol. 35 (2019) 133–151 [2] Andrievskaya, E. R. (2008). Journal of the European Ceramic Society, 28(12), 2363-2388. |
