Please use this identifier to cite or link to this item:
|Title:||High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide.|
|Authors:||CAPPIA FABIOLA; HUDRY DAMIEN; COURTOIS Eglantine; JANSSEN ARNE; LUZZI L.; KONINGS Rudy; MANARA Dario|
|Citation:||Materials Research Express vol. 1 no. 2 p. 025034|
|Type:||Articles in periodicals and books|
|Abstract:||Pioneering a so far unexplored research field, 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-ThO2 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-ThO2. Assessment of a semi-empirical relation between the Raman active T2g 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-ThO2 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 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.|
|JRC Directorate:||Nuclear Safety and Security|
Files in This Item:
There are no files associated with this item.
Items in repository are protected by copyright, with all rights reserved, unless otherwise indicated.