(Sr_(0.1)Th_(0.2)Nd_(0.3)La_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7)高熵烧绿石固化体的制备及化学稳定性

Preparation and Chemical Durability of (Sr_(0.1)Th_(0.2)Nd_(0.3)La_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7) High-Entropy Pyrochlore Immobilization

以金属硝酸盐为原材料,通过溶胶-喷雾热解-高温烧结法制备了(Sr_(0.1)Th_(0.2)Nd_(0.3)La_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7)高熵烧绿石固化体。利用X射线衍射(XRD)、扫描电镜(SEM)、Raman光谱对固化体结构进行表征,通过MCC-1浸出实验方法分析了固化体化学稳定性。研究结果表明:高熵烧绿石固化体为纯相高熵烧绿石结构,最佳烧结温度为1500℃。随着烧结温度增加,固化体晶粒和密度明显增加。浸出实验结果显示:La、Gd、Zr、Nd元素42 d归一化浸出率为10^(-6)g/(m^(2)·d)量级,Sr、Th元素的42 d归一化浸出率分别为10^(-5)g/(m^(2)·d)和10^(-3)g/(m^(2)·d)量级,固化体表现出良好的化学稳定性。

High-entropy pyrochlore immobilization(Sr_(0.1)Th_(0.2)Nd_(0.3)La_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7)was synthesized by sol-spray pyrolysis and high temperature sintering method using metal nitrate as raw materials. The microstructure of the immobilization was characterized by XRD, SEM and Raman spectroscopy, and the chemical durability was measured by the MCC-1 static aqueous leaching test. The results show that the immobilization exhibits single high-entropy phases of ordered pyrochlore structure, and the optimum sintering temperature is determined to be 1 500 ℃. With the sintering temperature raising, the grain size and the density of immobilization increase obviously. The leaching test indicates that the 42-day leaching rates of La, Gd, Zr and Nd are the order of 10^(-6)g/(m^(2)·d), the 42-day leaching rates of Sr and Th are 10^(-5)g/(m^(2)·d) and 10^(-3)g/(m^(2)·d) respectively. The high-entropy pyrochlore immobilization(Sr_(0.1)Th_(0.2)Nd_(0.3)La_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7)exhibits excellent chemical durability.