Crystal Structure Stability of Simulated Sr_1-1.5xY_xTiO₃（x=0-0.12） Waste Forms

【摘要】 A series of Sr_1-1.5xY_xTiO₃（x = 0-12） solid solutions were synthesized by a solid state reaction process.The effects of reaction temperature and dopant on the crystallinity,microstructure and morphology of Sr_1-1.5xY_xTiO₃（x=0-0.12） were investigated.Pure and single-phase perovskite-type Sr_1-1.5xY_xTiO₃（x<0.08） solid solutions were obtained at 1 400 ℃ for 6 h.The perovskite-type SrTiO₃ and pyrochlore-phase Y₂Ti₂O₇ coexisted for x = 0.08-0.12,leading to an unstable and unfavourable solid solution structure for long-term immobilization of the ⁹⁰Sr.The X-ray diffraction patterns for Rietveld refinement analysis confirmed the formation of a Sr_1-1.5xY_xTiO₃（x = 0-0.12） continuous solid solution.Stretching and bending vibrations were assigned in the infrared region.The SrTiO₃ grain size increased with Y content.The leaching behavior of Y³⁺ from the waste forms of Sr_1-1.5xY_xTiO₃ was controlled by its structural change.更多还原

【Abstract】 A series of Sr_1-1.5xY_xTiO₃（x = 0-12） solid solutions were synthesized by a solid state reaction process.The effects of reaction temperature and dopant on the crystallinity,microstructure and morphology of Sr_1-1.5xY_xTiO₃（x=0-0.12） were investigated.Pure and single-phase perovskite-type Sr_1-1.5xY_xTiO₃（x<0.08） solid solutions were obtained at 1 400 ℃ for 6 h.The perovskite-type SrTiO₃ and pyrochlore-phase Y₂Ti₂O₇ coexisted for x = 0.08-0.12,leading to an unstable and unfavourable solid solution structure for long-term immobilization of the ⁹⁰Sr.The X-ray diffraction patterns for Rietveld refinement analysis confirmed the formation of a Sr_1-1.5xY_xTiO₃（x = 0-0.12） continuous solid solution.Stretching and bending vibrations were assigned in the infrared region.The SrTiO₃ grain size increased with Y content.The leaching behavior of Y³⁺ from the waste forms of Sr_1-1.5xY_xTiO₃ was controlled by its structural change.更多还原