Phase relations,microstructure,and valence transition studies on CaZr1-xCexTi2O7(0.0≤x≤1.0)system  

作　　者：Weimin Li Faqin Dong Liang Bian Hao Zou Mianxin Song 

机构地区：[1]Research Center of Laser Fusion,China Academy of Engineering Physical,Mianyang 621900,China [2]Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory,Southwest University of Science and Technology,Mianyang 621010,China [3]Laboratory of Solid Waste Treatment and Resource Recycle,Ministry of Education,Southwest University of Science and Technology,Mianyang 621010,China [4]Hebei University of Geosciences,Shijiazhuang 050000,China

出　　处：《Journal of Rare Earths》2018年第11期1184-1189,共6页稀土学报（英文版）

基　　金：Project supported by Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk16,17LZX606);National Natural Science Foundation of China(41302027);973 project(2014CB8460003);One-Thousand-Talents Scheme in Sichuan Province;Hebei Outstanding Young Scholars;Science and Technology Program of Hebei Province(D2016403064,160446012 and 15211121)

摘　　要：In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 ℃ in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and X-ray photoelectron spectroscopy （XPS）. Phase relations of CaZrl xCexTi207 systems were determined by XRD analyses and Rietveld refinements. Four different phases are identified, namely zirconolite, perovskite, pyrochlore, and cerianite. The phase transformation （2M-zirconolite → 4M-zirconolite →Ce-pyrochlore） is caused by cations rearrangement as cerium content increases. The solubility limit of cerium ions in CaZrl .xCexTi207 system is estimated to be approximately 0.80. Under sintering air atmosphere, partial reduction of Ce^4＋ in Ce^3＋ is detected in Ce 3d XPS soectra, and the ratio of Ce^3＋ and Ce^4＋ significantly decreases as cerium content increases.In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 ℃ in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and X-ray photoelectron spectroscopy （XPS）. Phase relations of CaZrl xCexTi207 systems were determined by XRD analyses and Rietveld refinements. Four different phases are identified, namely zirconolite, perovskite, pyrochlore, and cerianite. The phase transformation （2M-zirconolite → 4M-zirconolite →Ce-pyrochlore） is caused by cations rearrangement as cerium content increases. The solubility limit of cerium ions in CaZrl .xCexTi207 system is estimated to be approximately 0.80. Under sintering air atmosphere, partial reduction of Ce^4＋ in Ce^3＋ is detected in Ce 3d XPS soectra, and the ratio of Ce^3＋ and Ce^4＋ significantly decreases as cerium content increases.

关 键 词：ZIRCONOLITE Ce-pyrochlore Phase relations Valence transition Rare earths 

分 类 号：O611.6[理学—无机化学]