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采用高温固相反应,以NaF作助熔剂,在1000°C的温度下合成了锕系元素Pu的模拟固化体(Gd1–xCex)2Zr2O7+x(0≤x≤0.7).研究了模拟固化体的物相、热膨胀系数(TEC)、热导率(TC)随温度及组成的变化规律.粉末X射线衍射(XRD)测试结果表明:Gd2Zr2O7基质本身呈弱有序烧绿石结构,而用Ce4+取代Gd3+的模拟固化体都呈缺陷萤石结构.(Gd1–xCex)2Zr2O7+x的Ce(3d)X射线光电子能谱(XPS)有六个峰,结合能分别位于881.7,888.1,897.8,900.4,907.1,916.1 e V处,与Ce O2的XPS图谱非常相似,说明Ce为四价.随着温度的升高,所有样品的热膨胀系数总体上呈增大趋势.在室温至750°C附近,大部分样品的热导率随温度的升高而降低,之后热导率又呈小幅上升.在相同温度下,固化体(Gd1–xCex)2Zr2O7+x(0≤x≤0.7)的热膨胀系数及热导率随组成变化呈相同趋势:在0≤x≤0.1范围内随x的增大而增大,随后在x=0.1–0.7时逐渐减小.
The simulated solidified body (Gd1-xCex) 2Zr2O7 + x (0≤x≤0.7) of actinide element Pu was synthesized by high-temperature solid-state reaction with NaF as a flux at a temperature of 1000 ° C. The simulated solidified body (TEC) and thermal conductivity (TC) with temperature and composition.The results of powder X-ray diffraction (XRD) showed that the matrix of Gd2Zr2O7 itself was weakly ordered pyrochlore structure, whereas Ce4 + The simulated solidified bodies substituted for Gd3 + were all characterized by a defect fluorite structure.The Ce (3d) X-ray photoelectron spectroscopy (XPS) of (Gd1-xCex) 2Zr2O7 + x had six peaks with binding energies of 881.7,888.1,897.8,900.4 , 907.1 and 916.1 eV, which is very similar to the XPS spectrum of Ce O2, indicating that Ce is tetravalent. As the temperature increases, the thermal expansion coefficients of all the samples increase generally. From room temperature to around 750 ° C, The thermal conductivity of most samples decreased with increasing temperature, and then the thermal conductivity increased slightly.At the same temperature, the thermal expansion coefficient of (Gd1-xCex) 2Zr2O7 + x (0≤x≤0.7) and The thermal conductivity changes with the composition of the same trend: in the range of 0 ≤ x ≤ 0.1 increases with increasing x, and then gradually decreases when x = 0.1-0.7.