Phase formation, stability, and oxidation in (Ti, Zr, Hf)NiSn half-Heusler compounds
| Autor: | Lassi Karvonen, Jürg Hulliger, Leyre Sagarna, Alessandra Beni, Anke Weidenkaff, Patrik Schmutz, Sascha Populoh, Krzysztof Gałązka, Wenjie Xie |
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| Rok vydání: | 2014 |
| Předmět: |
Kelvin probe force microscope
Materials science Metallurgy Analytical chemistry Surfaces and Interfaces Condensed Matter Physics Decomposition Surfaces Coatings and Films Electronic Optical and Magnetic Materials Phase (matter) Thermoelectric effect Oxidizing agent Microscopy Materials Chemistry Grain boundary Electrical and Electronic Engineering Thermal analysis |
| Zdroj: | physica status solidi (a). 211:1259-1266 |
| ISSN: | 1862-6300 |
| Popis: | Thermoelectric half-Heusler compounds with the nominal composition (Ti0.33Zr0.33Hf0.33)NiSn were synthesized and exposed to operating conditions, i.e., elevated temperatures and oxidizing atmosphere. As-prepared samples were found to be a stable multiphase system consisting of Ti- and (Zr,Hf)-rich phases with half-Heusler structure. The influence of an oxidizing atmosphere at elevated temperatures on the sample was studied in- and ex situ by optical and electron microscopy and thermal analysis. Exposure to air resulted in surface oxidation starting at T = 545 K. During a defined heat treatment the Ti-rich phase decomposed while the (Zr,Hf)-rich phase was stable. In situ Atomic Force Microscopy and Scanning Kelvin Probe Force Microscopy experiments confirmed that interfaces, especially grain boundaries, are most prone to phase decomposition. |
| Databáze: | OpenAIRE |
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