Abstract A series of Nd and Ce co-doped (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) pyrochlores were synthesized by flux method at 900–1000 °C using nitrates as starting materials and a small amount of NaF as fluxing agent. The influences of contents of Nd/Ce, fluxing agent and reaction temperature on the phase structure of the pyrochlores were systematically investigated by X-ray diffraction (XRD) and Raman spectroscopy (Raman). The chemical stability of Nd and Ce co-doped pyrochlore bulk ceramics was also evaluated. XRD and Raman results showed that the crystalline phase of (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) pyrochlores always remained a single disordered defect-fluorite structure for any x value. XRD, Raman spectrum and SEM-EDX results revealed that the Nd and Ce could be co-doped at the Gd-site and Zr-site of the Gd 2 Zr 2 O 7 pyrochlore structure, respectively. The normalized release rates of Gd, Zr, Nd and Ce in (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 pyrochlore bulk ceramics (x = 0.25, 0.5 and 0.75) remained relatively constant in a low value below 10 −4 g m −2 d −1 at 90 °C for 7 days, exhibiting superior chemical stability.

中文翻译：

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用于核废料形式的 Nd 和 Ce 共掺杂 (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) 烧绿石陶瓷的助熔剂合成和化学稳定性

摘要 采用助熔剂法在 900–1000 °C 下合成了一系列 Nd 和 Ce 共掺杂 (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) 烧绿石。硝酸盐为起始原料，少量 NaF 为助熔剂。通过X射线衍射(XRD)和拉曼光谱(Raman)系统研究了Nd/Ce含量、助熔剂和反应温度对烧绿石相结构的影响。还评估了 Nd 和 Ce 共掺杂烧绿石块状陶瓷的化学稳定性。XRD 和 Raman 结果表明 (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) 烧绿石的晶相始终保持单一的无序缺陷-萤石结构对于任何 x价值。XRD，拉曼光谱和SEM-EDX结果表明Nd和Ce可以分别共掺杂在Gd 2 Zr 2 O 7 烧绿石结构的Gd位和Zr位。Gd、Zr、Nd 和 Ce 在 (Gd 1-x Nd x ) 2 (Zr 1-x Ce x ) 2 O 7 烧绿石块状陶瓷（x = 0.25、0.5 和 0.75）中的归一化释放速率在在 90°C 下保持 7 天低于 10 -4 gm -2 d -1 的低值，表现出优异的化学稳定性。