La^(3+)掺杂BaAl_(2)Si_(2)O_(8)陶瓷的结构及微波介电性能  

Structure and Microwave Dielectric Properties of La^(3+)Doped BaAl_(2)Si_(2)O_(8)Ceramics

作　　者：肖竣文 丁士华[1] 张云 宋天秀[1] XIAO Junwen;DING Shihua;ZHANG Yun;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,四川成都610039

出　　处：《西华大学学报（自然科学版）》2023年第5期62-68,共7页Journal of Xihua University:Natural Science Edition

基　　金：国家自然科学基金(51902268);宜宾市科技计划项目(2021GY005);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：采用传统固相反应合成Ba_(1-x)La_(x)Al_(2)Si_(2)O_(8)(x=0,0.005,0.01,0.015,0.02),探讨不同La^(3+)取代量对Ba_(1-x)La_(x)Al_(2)Si_(2)O_(8)(BAS)陶瓷晶体结构和微波介电性能的影响,根据第一性原理计算讨论离子的取代位置,比较不同位置的形成能。结果表明:La^(3+)最有可能取代Ba^(2+);La^(3+)能有效地促进六方相向单斜相的转变,当x=0.02时,转化率达到98.71%,提高了品质因数(Q×f值)和谐振频率温度系数(τ_(f));烧结温度1400℃、x=0.01时Ba_(0.99)La_(0.01)Al_(2)Si_(2)O_(8)陶瓷表现出最佳介电性能,Q×f为25674 GHz,密度ρ为3.30 g/cm^(3),介电常数ε_(r)为6.938,谐振频率温度系数τ_(f)为−42.79×10^(-6)/℃。Ba_(1-x)La_(x)Al_(2)Si_(2)O_(8)(x=0,0.005,0.01,0.015,0.02)were synthesized by solid state reaction.Based on the first principle calculation,the replacement position was discussed.The formation energy of different sites was compared,and the result shows that it is most likely that La^(3+)replaced Ba^(2+).The crystal structure and microwave dielectric properties of Ba_(1-x)La_(x)Al_(2)Si_(2)O_(8)were investigated.The result shows that La^(3+)can effectively promote the transformation from hexacelsian to celsian,when x=0.02,the conversion ratio reaches 98.71%,and the quality factor(Q×f)value and the temperature coefficient of resonant frequency(τ_(f))are increased.when x=0.01,the Ba_(0.99)La_(0.01)Al_(2)Si_(2)O_(8)ceramics sintered at 1400℃exhibits the best dielectric properties:Q×f=25674 GHz,ρ=3.30 g/cm^(3),εr=6.938,τ_(f)=−42.79×10^(-6)/℃.

关 键 词：钡长石 单斜相 介电常数 离子取代 

分 类 号：TQ174[化学工程—陶瓷工业]