Densification kinetics of MnO-doped UO2-10 wt%Gd2O3 compact

The effect of MnO doping on the densification behavior of the UO2-10 wt%Gd2O3 compact has been investigated by using a high-temperature pushrod dilatometer up to 1650 °C. Dilatometry results show that small amounts of MnO enhance the sintering of the UO2-10 wt%Gd2O3 compact leading to a very high densification rate at low temperatures of about 1250 °C. The sintered density substantially was increased by more than 1% of the theoretical density in only 0.01 wt% of MnO added sample. A small amount of MnO also promotes the grain growth dramatically. The UO2-10 wt%Gd2O3 pellet with 0.1 wt% of MnO shows a 2.5 times larger grain size than the undoped UO2-10 wt%Gd2O3 pellet. These results might be attributed to the enhanced grain boundary mobility, which probably resulted from a large distortion of the surrounding lattice.