التفاصيل البيبلوغرافية
| العنوان: |
Fundamental material property trends in the La0.8-xNdxCa0.2FeO3-δ series: crystal structure and thermal expansion. |
| المؤلفون: |
Berger, Christian1 (AUTHOR), Bucher, Edith1 (AUTHOR) edith.bucher@unileoben.ac.at, Lammer, Judith2 (AUTHOR), Nader, Christina1 (AUTHOR), Sitte, Werner1 (AUTHOR) |
| المصدر: |
Journal of Materials Science. 2021, Vol. 56 Issue 17, p10191-10203. 13p. 1 Color Photograph, 2 Diagrams, 5 Charts, 4 Graphs. |
| مصطلحات موضوعية: |
*THERMAL expansion, *SCANNING transmission electron microscopy, *CRYSTAL structure, *MECHANICAL properties of condensed matter, *RIETVELD refinement |
| مستخلص: |
Compounds from the series La0.8-xNdxCa0.2FeO3-δ (0.1 ≤ x ≤ 0.7) were synthesised by a sol–gel route. X-ray diffraction and Rietveld analysis showed that materials with 0 ≤ x ≤ 0.6 crystallize as single-phase orthorhombic perovskites. The smaller ionic radius of Nd3+ compared to La3+ leads to a decrease in unit cell volume with increasing x. Elemental mapping by high-resolution scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy confirms the homogeneous distribution of the A-site elements (La, Nd and Ca) in the perovskite (ABO3) lattice. The thermal expansion behaviour of La0.8-xNdxCa0.2FeO3-δ (0 ≤ x ≤ 0.6) was characterized by dilatometry at 30 ≤ T/°C ≤ 1000 and 1 × 10–3 ≤ pO2/bar ≤ 1. The thermal expansion coefficients of La0.8-xNdxCa0.2FeO3-δ, which were determined in regions I (40–530 °C) and II (530–990 °C), respectively, are almost independent of the Nd concentration in the range of (0 ≤ x ≤ 0.6) and increase slightly with decreasing pO2. The transition from orthorhombic to trigonal modification, which is observed for La0.8Ca0.2FeO3-δ at approx. 740 °C, is suppressed for all Nd-substituted compounds with x ≥ 0.1. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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