The role of oxygen potential in the sintering of UO2–5wt%CeO2 powder mixed with M3O8 (M = U + Ce)

The sintering behavior of a UO2–5wt%CeO2 powder mixture was examined with different amounts of M3O8 (M = U + Ce) powder pulverized from a (U, Ce)O2 pellet by oxidation and in atmospheres with different oxygen potentials. The analysis revealed that a higher oxygen potential in the sintering atmosphere and a higher amount of M3O8 contributed to a lower sintered density but the formation of a larger average grain size in the microstructure of the sintered specimens. Moreover, it was revealed that the weight change during sintering with different amounts of M3O8 had an influence on the microstructural evolution and sintered density due to the difference in the oxygen potentials. This behavior is discussed in terms of the oxygen potential–density relationship, thermogravimetric behavior and microstructure evolution in the specimens.