Structural Characteristics and Thermophysical Properties of Complex Ceramic Oxides in the System Dy2O3–HfO2
- 100 Downloads
The structure and thermophysical properties of materials formed in the system Dy2O3–HfO2 (molar ratio 1 : 3 to 3 : 1) as a result of isothermal firing of x-ray amorphous mixed hydroxides at temperature to 1600°C are investigated. It is shown that for ratios 1 : 3 to 1 : 1 the crystallization process results in the formation of single-phase solid solutions with the structure of defective fluorite and marked nonequivalence of the parameters of the local environment of the Dy and Hf atoms. It is determined that the ceramic based on dysprosium hafnate (Dy2O3: HfO2 = 1 : 1) possesses low, practically temperature independent (to 800°C), thermal conductivity about 1.4 W/(m · K).
Key wordsdysprosium hafnate crystal lattice fluorite thermal conductivity
The Russian Scientific Foundation provided partial support for this work under grant No. 14-22-00098.
We thank Doctor of Chemical Sciences Profession A. V. Belyakov who was deeply familiar with the material presented here and made a number of valuable remarks.
- 2.P. A. Arsen’ev, V. B. Glushkova, A. A. Evdokimov, et al., Compounds of Rare Earth Elements: Zirconates, Hafnates, Niobates, Tantalates, Antimonides [in Russian], Nauka, Moscow (1985).Google Scholar
- 3.V. N. Vladimirov, E. S. Lukin, N. A. Popova, et al., “New types of refractory heat-insulation materials for long-term use at extremely high temperature,” Steklo Keram., No. 4, 14 – 21 (2011); V. S. Vladimirov, E. S. Lukin, N. A. Popova, et al., “New types of light-weight refractory and heat-insulation materials for long-term use at extremely high temperatures,” Glass Ceram., 68(3 – 4), 116 – 122 (2011).Google Scholar
- 9.J. Emsley, The Elements [Russian translation], Mir, Moscow (1993).Google Scholar
- 16.V. Petricek, M. Dusek, L. Palatinus, Jana: The Crystallographic Computing System, Inst. Physics, Praha, Czech. Republic (2006).Google Scholar
- 17.V. V. Popov, A. P. Menushenkov, Ya. V. Zubavichus, et al., “Trends in formation of the nanocrystalline structure and cationic ordering in the Dy2O3–HfO2 (1 : 1) system,” Russ. J. Inorg. Chem., 58(3), 331 – 337 (2013).Google Scholar
- 18.V. V. Popov, V. F. Petrunin, and S. A. Korovin, Method of Obtaining Nanocrystalline Powders and Ceramic Materials Based on Mixed Oxides of Rare-Earth Elements and Methods of Subgroup IVB, RF Patent 2467983, IPC C04B 35/46; published Nov. 27, 2012.Google Scholar
- 19.A. V. Belyakov and E. B. Bendovskii, “Fabrication of single-phase dense ceramic from high-sintering complex oxides,” Steklo Keram., No. 6, 23 – 28 (2015); A. V. Belyakov and E. B. Bendovskii, “Fabrication of single-phase dense ceramic from high-sintering complex oxides new types of light-weight refractory and heat-insulation materials for long-term use at extremely high temperatures,” Glass Ceram., 72(5 – 6), 206 – 211 (2015).Google Scholar