Thermodynamics and nonstoichiometry in the intermetallic compound Pt 3 In
| Autor: | Xiaohong Wu, Hans-Jürgen Schaller, Friedrich Gehringer, Zhiyu Qiao, Herbert Ipser, Wenxia Yuan, Yongzhang Huang, Agnes Schweitzer, Jens Dischinger |
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| Rok vydání: | 2004 |
| Předmět: |
Diffraction
Materials science Mechanical Engineering Metals and Alloys Intermetallic chemistry.chemical_element General Chemistry Electrolyte Crystallographic defect Crystallography Lattice constant chemistry Mechanics of Materials Homogeneity (physics) Materials Chemistry Physical chemistry Platinum Indium |
| Zdroj: | Intermetallics. 12:401-406 |
| ISSN: | 0966-9795 |
| DOI: | 10.1016/j.intermet.2003.12.004 |
| Popis: | Thermodynamic activities of indium were measured between 973 and 1273 K in the nonstoichiometric intermetallic compound Pt 3 In using an emf-method based on an oxygen conducting solid electrolyte. The variation of the lattice parameter with composition was determined by powder X-ray diffraction, and the corresponding results point to a considerably wider homogeneity range on the indium-rich side than previously reported. The results of the activity measurements are interpreted in terms of a statistical-thermodynamic model for L1 2 -phases considering four types of point defects, i.e. anti-structure atoms and vacancies on the platinum and indium sublattices. The energies of formation of the point defects at the stoichiometric composition are estimated from a curve fitting procedure yielding E f (Pt In )= E f (In Pt )=1.15 eV, assuming that E f V (Pt)= E f V (In)=2.0 eV. This results in a disorder parameter α ′=5·10 −6 at 1173 K which means that at the stoichiometric composition 0.002% of the indium sublattice sites are occupied by platinum atoms and 0.0007% of the platinum sites by indium atoms at this temperature. |
| Databáze: | OpenAIRE |
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