Densification Behaviors of UO2-CeO2 System

Specimens of the pseudo-binary (U3O8) 1-x. (CeO2) x system were prepared by solid-solid reaction in an oxidizing atmosphere. A wide range of solubility was encountered and a preliminary phase diagram was consequently constructed, with a single phase region observed in the range 60-80 mole % CeO2. Densification behaviors of powdered compound (30 mole% U3O8-70 mole % CeO2) were investigated under an oxidizing atmosphere. The densification curve exhibited three separate sintering stages which were later confirmed by an SEM- investigation of the microstructure of sintered compacts. The grain growth was clearly enhanced at the initial stages but seemed to slow down later and almost come to a halt at the saturation limits. This behavior was discussed in terms of current theoretical models. (author)