Thermodynamic evaluation of the germanium-lutetium and dysprosium-germanium binary systems
| Autor: | Hassan Azza, L. Bouirden, Rkia Tamim, N. Selhaoui, Abdellah Iddaoudi, Khadija Achgar |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
General Chemical Engineering Intermetallic Thermodynamics chemistry.chemical_element Germanium 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Computer Science Applications Gibbs free energy symbols.namesake chemistry Homogeneity (physics) symbols Dysprosium Condensed Matter::Strongly Correlated Electrons 0210 nano-technology CALPHAD Phase diagram Solid solution |
| Zdroj: | Calphad. 62:18-29 |
| ISSN: | 0364-5916 |
| DOI: | 10.1016/j.calphad.2018.05.001 |
| Popis: | The Ge-Lu and Dy-Ge binary systems have been optimized using the available experimental data on phase diagrams and thermodynamic functions by means of the CALPHAD approach. The Ge-Lu system contains seven phases based on six intermetallic compounds: Ge1.8Lu, Ge3Lu2, Ge5Lu4, Ge10Lu11, Ge4Lu5, and Ge3Lu5, which were all treated as stoichiometric compounds. For the Dy-Ge system seven intermetallic compounds were found: Dy5Ge3, Dy5Ge4, DyGe, Dy2Ge3, Dy3Ge5, DyGe2 and DyGe3. These phases were stoichiometric except Dy5Ge3 that has a homogeneity range, was treated by a two-sublattice model with substitution in each sublattice. A solution model has been used for the description of the excess term of the Gibbs energy for the liquid phase and the solid solution for the Dy-Ge system. The Ge-Lu system was examined using two different descriptions of the liquid phase: exponential dependence of temperature (Kaptay model) and linear dependence (Redlich-Kister model). The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values available in the literature. The process of modeling allows us to calculate the phase equilibria and thermodynamic properties of the liquid phase and intermetallic compounds for the first time. The results obtained are reported in a series of figures and tables in this manuscript. |
| Databáze: | OpenAIRE |
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