High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide
The behaviour from 1500 K up to melting of nanocrystalline (nc) thorium dioxide, the refractory binary oxide with the highest melting point (3651 K), was explored here for the first time using fast laser heating, multi-wavelength pyrometry and Raman spectroscopy for the analysis of samples quenched...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2014-01-01
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| Series: | Materials Research Express |
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| Online Access: | https://doi.org/10.1088/2053-1591/1/2/025034 |
| _version_ | 1797747233157808128 |
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| author | F Cappia D Hudry E Courtois A Janßen L Luzzi R J M Konings D Manara |
| author_facet | F Cappia D Hudry E Courtois A Janßen L Luzzi R J M Konings D Manara |
| author_sort | F Cappia |
| collection | DOAJ |
| description | The behaviour from 1500 K up to melting of nanocrystalline (nc) thorium dioxide, the refractory binary oxide with the highest melting point (3651 K), was explored here for the first time using fast laser heating, multi-wavelength pyrometry and Raman spectroscopy for the analysis of samples quenched to room temperature. Nc-ThO _2 was melted at temperatures hundreds of K below the melting temperature assessed for bulk thorium dioxide. A particular behaviour has been observed in the formed liquid and its co-existence with a partially restructured solid, possibly due to the metastable nature of the liquid itself. Raman spectroscopy was used to characterize the thermal-induced structural evolution of nc-ThO _2 . Assessment of a semi-empirical relation between the Raman active T _2g mode peak characteristics (peak width and frequency) and crystallites size provided a powerful, fast and non-destructive tool to determine local crystallites growth within the nc-ThO _2 samples before and after melting. This semi-quantitative analysis, partly based on a phonon-confinement model, constitutes an advantageous, more flexible, complementary approach to electron microscopy and powder x-ray diffraction (PXRD) for the crystallite size determination. The adopted experimental approach (laser heating coupled with Raman spectroscopy) is therefore proven to be a promising methodology for the high temperature investigation of nanostructured refractory oxides. |
| first_indexed | 2024-03-12T15:48:50Z |
| format | Article |
| id | doaj.art-5bc4f6325b454c05a4878039d23bebc4 |
| institution | Directory Open Access Journal |
| issn | 2053-1591 |
| language | English |
| last_indexed | 2024-03-12T15:48:50Z |
| publishDate | 2014-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Materials Research Express |
| spelling | doaj.art-5bc4f6325b454c05a4878039d23bebc42023-08-09T15:19:20ZengIOP PublishingMaterials Research Express2053-15912014-01-011202503410.1088/2053-1591/1/2/025034High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxideF Cappia0D Hudry1E Courtois2A Janßen3L Luzzi4R J M Konings5D Manara6European Commission, Institute for Transuranium Elements, PO Box 2340, 76125 Karlsruhe, Germany; Politecnico di Milano, Department of Energy, ‘Enrico Fermi’ Center for Nuclear Studies, via Ponzio, 34/3—20133 Milan, ItalyEuropean Commission, Institute for Transuranium Elements, PO Box 2340, 76125 Karlsruhe, GermanyKarlsruhe Institute of Technology, Institute for Nanotechnology, 76344 Eggenstein-Leopoldshafen, GermanyEuropean Commission, Institute for Transuranium Elements, PO Box 2340, 76125 Karlsruhe, GermanyPolitecnico di Milano, Department of Energy, ‘Enrico Fermi’ Center for Nuclear Studies, via Ponzio, 34/3—20133 Milan, ItalyEuropean Commission, Institute for Transuranium Elements, PO Box 2340, 76125 Karlsruhe, GermanyEuropean Commission, Institute for Transuranium Elements, PO Box 2340, 76125 Karlsruhe, GermanyThe behaviour from 1500 K up to melting of nanocrystalline (nc) thorium dioxide, the refractory binary oxide with the highest melting point (3651 K), was explored here for the first time using fast laser heating, multi-wavelength pyrometry and Raman spectroscopy for the analysis of samples quenched to room temperature. Nc-ThO _2 was melted at temperatures hundreds of K below the melting temperature assessed for bulk thorium dioxide. A particular behaviour has been observed in the formed liquid and its co-existence with a partially restructured solid, possibly due to the metastable nature of the liquid itself. Raman spectroscopy was used to characterize the thermal-induced structural evolution of nc-ThO _2 . Assessment of a semi-empirical relation between the Raman active T _2g mode peak characteristics (peak width and frequency) and crystallites size provided a powerful, fast and non-destructive tool to determine local crystallites growth within the nc-ThO _2 samples before and after melting. This semi-quantitative analysis, partly based on a phonon-confinement model, constitutes an advantageous, more flexible, complementary approach to electron microscopy and powder x-ray diffraction (PXRD) for the crystallite size determination. The adopted experimental approach (laser heating coupled with Raman spectroscopy) is therefore proven to be a promising methodology for the high temperature investigation of nanostructured refractory oxides.https://doi.org/10.1088/2053-1591/1/2/025034nanocrystalline thorium dioxidemelting point depressionfast laser heatingmicro-Raman spectroscopy |
| spellingShingle | F Cappia D Hudry E Courtois A Janßen L Luzzi R J M Konings D Manara High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide Materials Research Express nanocrystalline thorium dioxide melting point depression fast laser heating micro-Raman spectroscopy |
| title | High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide |
| title_full | High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide |
| title_fullStr | High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide |
| title_full_unstemmed | High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide |
| title_short | High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide |
| title_sort | high temperature and melting behaviour of nanocrystalline refractory compounds an experimental approach applied to thorium dioxide |
| topic | nanocrystalline thorium dioxide melting point depression fast laser heating micro-Raman spectroscopy |
| url | https://doi.org/10.1088/2053-1591/1/2/025034 |
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