Structure and Chemical Durability of Actinide Nuclides Solidified by High-Entropy Pyrochlore(La1/6Pr1/6Nd1/6Sm1/6Eu1/6Gd1/6)2Zr2O7
High-entropy ceramics(HECs)are a potential target for high-level waste curing due to their excellent phase and chemical stability.In this work,a high-entropy rare-earth zirconate pyrochlore(La1/6Pr1/6Nd1/6Sm1/6Eu1/6Gd1/6)2Zr2O7 was designed.And the lanthanide element Ce was used as simulated radioactive actinide nuclides.A series of ceramic solidifications(La1/6Pr1/6 Nd1/6 Sm1/6 Eu1/6 Gd1/6)2(Zr1-XCex)2O7(0≤X≤0.5)were prepared using a high temperature solid phase method to solidify Ce.The solidifying performances were evaluated by analyzing the physical phase composition,microstructure,microscopic morphology,and anti-leaching.The results show that all the nuclides are uniformly solidly dissolved into crystal structure.As the CeO2 content increases,the crystal structure changes from an ordered pyrochlore phase to a defective fluorite phase.The normalized leaching rates of Ce range from 10-7 g·m-2·d-1 to10-6g·m-2·d-1,showing excellent chemical stability.
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