LnPO·nHO rhabdophane/monazite is an important actinide-bearing material in the back end of the nuclear fuel cycle. In this work, using Nd to simulate trivalent actinides, CeNdPO·0.667HO rhabdophane was synthesized by the wet-chemistry method in 90 °C and pH = 1 solution. The sintering behavior of associated CeNdPO monazite ceramics was investigated by pressureless sintering and spark plasma sintering (SPS), along with appraising their chemical stability. The results reveal that Ce is successfully replaced by Nd in the rhabdophane lattice, and rhabdophane can transform to monazite with a temperature over 750 °C. SPS can compact the ceramic sample at a lower temperature compared to pressureless sintering even if the grain size is smaller. Adding a pre-sintering process of 900 °C before SPS and pressureless sintering will further improve the density and Vickers hardness of ceramics. For the chemical stability of CeNdPO monazite ceramics, Ce is more likely to be leached compared to Nd, and the ceramics prepared by SPS with a pre-sintering process have the lowest normalized leaching rates, associated with the values of 2.03 × 10 g·md and 0.75 × 10 g·m·d for Ce and Nd, respectively.

中文翻译：

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无压烧结和放电等离子烧结(SPS)制备Ce0.5Nd0.5PO4独居石陶瓷及其性能

LnPO·nH2O 棒石/独居石是核燃料循环后端重要的含锕系材料。本工作以Nd模拟三价锕系元素，在90 ℃、pH = 1的溶液中，采用湿化学法合成了CeNdPO·0.667H2O弹状多芬烷。通过无压烧结和放电等离子烧结 (SPS) 研究了相关 CeNdPO 独居石陶瓷的烧结行为，并评估了其化学稳定性。结果表明，杆状稀土晶格中的Ce成功被Nd取代，并且杆状稀土在750℃以上的温度下可以转变为独居石。与无压烧结相比，SPS 可以在较低的温度下压实陶瓷样品，即使晶粒尺寸较小。在SPS和无压烧结之前增加900℃的预烧结工艺，将进一步提高陶瓷的密度和维氏硬度。对于CeNdPO独居石陶瓷的化学稳定性来说，Ce比Nd更容易被浸出，并且通过SPS预烧结工艺制备的陶瓷具有最低的归一化浸出率，与2.03 × 10 g·md值相关Ce 和 Nd 分别为 0.75 × 10 g·m·d。