Performance change and aqueous durability analysis of Nd-doped Gd2Zr2O7 nanocrystalline ceramics

Abstract

In this work, Nd3+ was used as a substitution and it was incorporated into Gd2Zr2O7 nanocrystalline ceramics to simulate the immobilization of trivalent actinide elements. Gd2-xNdxZr2O7 (0.0 ≤ x ≤ 2.0) nanocrystalline powders were prepared by solvothermal method, and then sub-microcrystalline ceramics were obtained through self-propagating chemical furnace plus quick pressing (SCF/QP) technology. All powders are in defect fluorite structure, and Nd doping slightly changes the powder grain size. After analyzing the sintered ceramics, it can be found that the transition from defect fluorite structure to pyrochlore structure occurs when x ≥ 1.5. The sample density decreases with elevated Nd content, while the grain size gradually increases. Besides, the normalized release rates of Nd and Zr elements in the Nd2Zr2O7 waste form are kept in low values (below 10−5 g•m−2•d−1), which exhibits its excellent aqueous durability.