Teixeira, Silvio Rainho [UNESP]Imakuma, Kengo2014-05-272014-05-271991-01-01Journal of Nuclear Materials, v. 178, n. 1, p. 33-39, 1991.0022-3115http://hdl.handle.net/11449/64101The surface oxidation of UO2 sintered plates at 170-275 ° C was studied in situ by high temperature X-ray diffractometry. At very low oxygen concentration, UO2 is oxidized to U4O9, while at 300°C and argon-20 vol% oxygen it is oxidized up to U3O7. X-ray diffraction profiles of the UO2, U4O9 and U3O7 phases were well characterized during the transformations. The activation energy for the transformation of UO2 to U4O9, obtained from X-ray diffraction data, was found to be 117 ± 9 kJ/mol and 90 ± 14 kJ/mol for the β-(311) and α-(200) reflections, respectively. © 1991.33-39engChemical Reactions--Radiation EffectsX-rays--DiffractionActivation EnergySintered PlatesUranium DioxideArtigo10.1016/0022-3115(91)90453-EAcesso restrito2-s2.0-00257926379256541983393135