Solid-solid Reaction of Gd₂O₃-Nd₂O₃-ZrO₂-CeO₂ System at High Temperature

To investigate solid-solid reactions of Gd₂O₃-Nd₂O₃-ZrO₂-CeO₂ quaternary oxide system at high temperature conditions, using the mixed powders of Gd₂O₃, Nd₂O₃, ZrO₂ and CeO₂ as raw materials, a series of samples were prepared at the calcinations temperature of 1 673 K or 1 773 K in duration time of 24, 48 and 72 h, respectively. By analysis of XRD and SEM for the as-gained samples, the results indicate that Gd_2-xNd_xZr_2-xCe_xO₇ (0≤x≤2) crystalline compounds are synthesized, which possess oxygen-deficient fluorite phase companying with minor pyrochlore phase. As the rising of calcination temperature and/or the extending of calcination time, more pyrochlore phase and larger grain size and minor unknown phase are observed in the as-synthesized samples. Finally, the potential applications of zircon-based ceramic waste forms loading multi-nuclide were discussed and the related hotspot issues in future were presented as well.