Low-Temperature Thermodynamic Functions of Gadolinium Hafnate (Gd2Hf2O7)
| Autor: | Ya. S. Tischenko, D. S. Korablov, S. M. Lakiza, N. P. Gorbachuk, A. R. Kopan |
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| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Gadolinium Enthalpy Metals and Alloys Analytical chemistry chemistry.chemical_element 02 engineering and technology Calorimetry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Heat capacity Gibbs free energy symbols.namesake chemistry Mechanics of Materials Additive function 0103 physical sciences Materials Chemistry Ceramics and Composites symbols Isobar 0210 nano-technology Adiabatic process |
| Zdroj: | Powder Metallurgy and Metal Ceramics. 57:336-343 |
| ISSN: | 1573-9066 1068-1302 |
| Popis: | The isobar heat capacity of Gd2Hf2O7 is studied for the first time by adiabatic calorimetry in the range 80–298.15 K. It is shown that Cp of gadolinium hafnate changes monotonically and no anomalies are observed. The temperature dependences of the principal thermodynamic functions of Gd2Hf2O7 in the range 10–300 K are established. The heat capacity, entropy, reduced Gibbs energy, and enthalpy are determined for standard conditions: $$ {C}_p^{\circ } $$ (298.15 K) = 224.2 ± 0.9 J × × mol–1·K–1, S°(298.15 K) = 237.1 ± 2 J · mol–1 · K–1, Φ′ (298.15 K) = 109.4 ± 1.6 J · mol–1 · K–1, and H°(298.15 K) – H°(0 K) = 38084 ± 190 J · mol–1. The temperature dependence of the Gd2Hf2O7 heat capacity is evaluated using the Neumann–Kopp rule of additivity. The difference between the experimental and evaluated heat capacities of Gd2Hf2O7 in the range 80–298.15 K is no more than 3.4%, while the difference in $$ {C}_p^{\circ } $$ (298.15 K) is 0.4%. |
| Databáze: | OpenAIRE |
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