6533b827fe1ef96bd1285cd3
RESEARCH PRODUCT
On the origin of the sigmoid shape in the UO2 oxidation weight gain curves
Lionel DesgrangesJean-claude NiepceMichèle PijolatVincent BouineauGianguido BaldinozziArnaud PoulesquenNadine MillotL. Quémardsubject
Materials scienceAnalytical chemistryNucleationOxideNuclear applications02 engineering and technologyUO2010402 general chemistryKinetic energy01 natural sciencesIsothermal processchemistry.chemical_compoundElectron microscopyMaterials Chemistry[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process EngineeringEnvironmental scanning electron microscope[ SPI.GPROC ] Engineering Sciences [physics]/Chemical and Process Engineering021001 nanoscience & nanotechnology0104 chemical sciencesThermogravimetryCrackingchemistryCeramics and Composites0210 nano-technologySingle crystalX-ray methodsdescription
International audience; Cracking and spalling are known to occur during the oxidation of UO2. However, these phenomena are not considered by the existing kinetic models of the oxidation of UO2 into U3O8. In this study the oxidation of UO2 samples of various sizes from the single crystal to nanopowders, has been followed by isothermal and isobaric thermogravimetry, environmental scanning electron microscopy and in situ X-ray diffraction at temperatures ranging from 250 to 370°C in air. It has been shown that cracking occurs once a critical layer thickness of intermediate oxide has been reached, which corresponds to the beginning of the sigmoid kinetic curve. Cracking contribution to the sigmoid kinetic curve is then discussed as a function of temperature, and on the basis of nucleation and growth processes.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-10-01 | Journal of the European Ceramic Society |