Utilizza questo identificativo per citare o creare un link a questo documento:
|Titolo:||High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide|
|Autori interni:||LUZZI, LELIO|
|Data di pubblicazione:||2014|
|Rivista:||MATERIALS RESEARCH EXPRESS|
|Abstract:||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 (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.|
|Appare nelle tipologie:||01.1 Articolo in Rivista|
File in questo prodotto:
|Materials_Research_Express_1_(2014)_025034_1-12.pdf||1.06 MB||Adobe PDF||Post-print||Accesso riservato|
- PubMed Central loading...
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.