Preparation and Chemical Durability of (Sr_0.1Th_0.2Nd_0.3La_0.2Gd_0.2)₂Zr₂O₇ High-Entropy Pyrochlore Immobilization

High-entropy pyrochlore immobilization (Sr_0.1Th_0.2Nd_0.3La_0.2Gd_0.2)₂Zr₂O₇ 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/(m²·d), the 42-day leaching rates of Sr and Th are 10^-5 g/(m²·d) and 10^-3 g/(m²·d) respectively. The high-entropy pyrochlore immobilization (Sr_0.1Th_0.2Nd_0.3La_0.2Gd_0.2)₂Zr₂O₇ exhibits excellent chemical durability.