Li(Al_(1-x)Be_(x))SiO_(4)陶瓷的结构及微波介电性能  

Structure and Microwave Dielectric Properties of Li(Al_(1-x)Bex)SiO_(4)Ceramics

作　　者：王亚荣 丁士华[1] 张云 肖竣文 侯正鹏 蒋希 宋天秀[1] WANG Yarong;DING Shihua;ZHANG Yun;XIAO Junwen;HOU Zhengpeng;JIANG Xi;SONG Tianxiu(School of Materials Science and Engineering,Xihua University,Chengdu 610039,China)

机构地区：[1]西华大学材料科学与工程学院,成都610039

出　　处：《中国陶瓷》2023年第9期11-19,共9页China Ceramics

基　　金：国家自然科学基金(51902268);四川省科技厅重点研发项目(2021YFG0235);四川省粉末冶金工程技术研究中心开放课题重点项目(SC-FMYJ2020-02)。

摘　　要：采用传统的固相反应法合成了Li(Al_(1-x)Be_(x))SiO_(4)(x=0.005,0.01,0.02,0.03)陶瓷,为了确定Be^(2+)进入晶格后所占据的位置,通过CASTEP提供的第一性原理的密度泛函理论计算了Be^(2+)所占据的LiAlSiO_(4)(LAS)不同位置的缺陷形成能和体系总能量,结果表明,Be^(2+)占据Al位的LAS体系能量最低,最稳定。探究Be^(2+)取代Al^(3+)对Li(Al_(1-x)Be_(x))SiO_(4)(x=0.005,0.01,0.02,0.03)陶瓷的体密度、相组成、烧结特性、微观形貌和微波介电性能的影响。在掺杂Be^(2+)之后,烧结温度从1300℃(x=0)降低到1225℃(x=0.03),同时显著提升了LAS陶瓷的品质因数(Q×f)值和谐振频率温度系数(τf),能有效降低其介电常数。Li(Al_(0.995)Be_(0.005))SiO_(4)陶瓷在1325℃烧结10 h,具有良好的微波介电性能:ε_(r)=3.2,Q×f=44398 GHz,τ_(f)=45.2×10^(-6)℃^(-1)。Li(Al_(1-x)Be_(x))SiO_(4)(x=0.005,0.01,0.02,0.03)ceramics were synthesized via a traditional solid phase reaction method with different sintering temperatures.In order to determine the positions occupied by Be^(2+)into the lattice,the defect formation energies and total energies of various sites of LiAlSiO_(4)(LAS)occupied by Be^(2+)were discussed,the energies of LiAlSiO_(4)(LAS)systems were calculated using density functional theory of first-principle supplied by CASTEP.The result demonstrated that occupying the Alsite had the lowest total energies,so Be^(2+)should substitute Al^(3+).The impacts of replacing Al^(3+)with Be^(2+)on Li(Al_(1-x)Be_(x))SiO_(4)(x=0.005,0.001,0.002,0.003)ceramics were thoroughly studied,including the bulk density,sintering property,phase composition,microstructure,and microwave dielectric properties.With Be^(2+)-doping,the sintering temperature reduced from 1300℃(x=0)to 1225℃(x=0.03),and the Q×f value andτf value of LAS ceramics were significantly enhanced.Typically,the Li(Al_(0.995)Be_(0.005))SiO_(4)ceramic can be fully sintered at 1325℃for 10 h to obtain a supreme microwave dielectric properties:ε_(r)=3.2,Q×f=44398 GHz,τ_(f)=45.2×10^(-6)℃^(-1)respectively.

关 键 词：LAS 微波介电性能 低介电常数 第一性原理 

分 类 号：TQ174.75[化学工程—陶瓷工业]