Rapid preparation of Nd-doped zirconia ceramics for high-level radioactive waste immobilization

Abstract

Rapid preparation of ceramic waste form at low temperature is of great engineering significance for immobilization of high-level radioactive waste. Herein, we demonstrated that Nd-doped zirconia ceramics can be rapidly prepared at low sintering temperature with the assistance of hydrothermal assisted sol-gel method. The effects of sintering temperature and Nd content on the phase and microstructure evolutions of the obtained ceramics were studied. With the increasing content of Nd, the phase of ZrO2 transformed from monoclinic to cubic at first, then the pyrochlore Nd2Zr2O7 phase appeared, and finally hexagonal neodymia solid solution structure formed. Moreover, the grain size and compactness of the obtained ceramics increased with the increment in sintering temperature. The successful accommodation of Nd within the ZrO2 lattice was revealed by the detected increase of cell parameters. This work demonstrated that the hydrothermal assisted sol-gel process can be employed to effectively synthesize the Nd-doped zirconia ceramics as potential hosts for HLW immobilization.