Ce^(4+)掺杂钙钛锆石(CaZr_(1-x)Ce_(x)Ti_(2)O_(7))相变行为的研究  

Phase Evolution of Ce-doped Zirconolite CaZr_(1-x)Ce_(x)Ti_(2)O_(7) Ceramics

作　　者：提学超 罗意 宋功保[2] 李伟民[2] 董小磊 Ti Xuechao;Luo Yi;Song Gongbao;Li Weimin;Dong Xiaolei(Department of Automotive Engineering,Sichuan Aerospace Vocational College,Guanghan 618300,China;School of Materials Science and Engineering,Southwest University of Science and Technology,Mianyang 621000,China)

机构地区：[1]四川航天职业技术学院汽车工程系,四川广汉618300 [2]西南科技大学材料科学与工程学院,四川绵阳621000

出　　处：《中国稀土学报》2021年第2期287-293,I0003,共8页Journal of the Chinese Society of Rare Earths

基　　金：国家863项目(2009AA050703)资助。

摘　　要：采用高温固相反应法制备了CaZr_(1-x)Ce_(x)Ti_(2)O_(7)(0.0≤x≤1.0)系列钙钛锆石样品,借助X射线衍射(XRD)、拉曼光谱(Raman)、背散射电子像(BES)和能谱(EDS)分析,对其相变行为进行了研究。结果表明:随着Ce^(4+)掺杂量的增加,钙钛锆石(CaZrTi_(2)O_(7))表现出有规律的向烧绿石(CaCeTi_(2)O_(7))转变。当x≤0.2时,CaZr_(1-x)Ce_(x)Ti_(2)O_(7)样品为单一的钙钛锆石-2M相;0.3≤x≤0.5,部分钙钛锆石-2M结构发生重排(ZrO_(7)→ZrO_(8),TiO_(5)→TiO_(6))向钙钛锆石-4M结构转变,两种晶型共存。Ce^(4+)取代Zr^(4+)量达到60%~70%(0.6≤x≤0.7)时,钙钛锆石-2M相消失;钙钛锆石-4M向烧绿石转变,烧绿石为次晶相;而0.8≤x≤1.0时,样品转变为单一烧绿石相,且烧绿石晶格中阴阳离子的有序化程度随着x取值的增加而增加。这种相变规律也由样品晶粒的BES和EDS分析得到证实。A series of compositions with general stoichiometry CaZr_(1-x)Ce_(x)Ti_(2)O_(7)(0.0≤x≤1.0)were prepared by high-temperature solid-state reaction of component oxides and characterized by powder XRD,Raman spectroscopy,backscattered electrons(BES)and EDS analyses.The phase evolution from zirconolite(CaZrTi_(2)O_(7))to pyrochlore(CaCeTi_(2)O_(7))was elucidated with increasing concentration of Ce^(4+)(viz.x)in the compositions.The x≤0.2 single zirconolite-2 M phase is observed,while partly the zirconolite-2 M structure rearrangement(ZrO_(7)→ZrO_(8),TiO_(5)→TiO_(6))occurs resulting in the formation of zirconolite-4 M structure in the composition with 0.3≤x≤0.5,zirconolite-4 M as a coexisting phase.At higher substitution levels of Ce^(4+)ions(0.6≤x≤0.7),partly the zirconolite-4 M converts into pyrochlore,simultaneously zirconolite-2 M completely disappeared;while 0.8≤x≤1.0,pyrochlore is observed as single phase and the ordering of the anions-cations in pyrochlore lattice increases with increase in x.Further,the composition and microstructure of coexisting phases were verified by BES and EDS studies.

关 键 词：钙钛锆石 烧绿石 相关系 有序化 稀土 

分 类 号：TL941[核科学技术—辐射防护及环境保护]