低介电常数Mg_(x)Zn_(1.8-x)SiO_(3.8)微波陶瓷的结构与性能  

Structure and properties of Mg_(x)Zn_(1.8-x)SiO_(3.8) microwave ceramics with low dielectric constant

作　　者：段佳露 周港怀 刘绍军[1] DUAN Jialu;ZHOU Ganghuai;LIU Shaojun(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2022年第3期276-283,共8页Materials Science and Engineering of Powder Metallurgy

基　　金：湖南省自然科学基金资助项目(2021JJ30831)。

摘　　要：采用传统固相合成法制备硅锌矿结构Mg_(x)Zn_(1.8-x)SiO_(3.8)(x=0~0.4)陶瓷,结合X射线衍射谱、拉曼光谱、扫描电镜和网络矢量分析仪等,研究Mg掺杂对低介电常数Zn_(1.8)SiO_(3.8)基微波陶瓷的晶体结构、微观形貌与微波性能的影响。结果表明:在1 300℃烧结温度下,随Mg掺杂量x增加,Mg_(x)Zn_(1.8-x)SiO_(3.8)微波陶瓷的理论极化率减小,相对介电常数相应减小;氧四面体的平均扭转度先减小后增大,导致谐振频率温度系数先减小后增大;由Zn(1)/Mg(1)O_(4)、Zn(2)/Mg(2)O_(4)、和SiO_(4)四面体组成的六元环对称性增强;同时Zn(Mg)-O键长减小,键能增大,导致品质因子Q×f增大。Mg_(0.4)Zn_(1.4)Si O_(3.8)陶瓷性能优异,相对介电常数ε_(r)约为6.2,Q×f约为112 100 GHz,谐振频率温度系数τ_(f)约为-19.2×10^(-6)℃。Mg_(x)Zn_(1.8-x)SiO_(3.8)(x=0,0.1,0.2,0.3,0.4) microwave ceramics with willemite structure were prepared by the traditional solid-phase synthesis method.The effect of Mg on crystal structure,microstructure and dielectric properties of Mg;Zn;Si O;ceramics were characterized on the basis of X-ray diffraction,raman spectroscopy,and scanning electron microscopy and vector network analyzer.The results show that the theoretical polarizability of Mg_(x)Zn_(1.8-x)SiO_(3.8) microwave ceramics decreases,and the relative permittivity decreases correspondingly with the increase of doping Mg amount x of sintering temperature at 1 300℃.With the increase of x,the average twist of oxygen tetrahedron decreases first and then increases,resulting in the temperature coefficient of resonant frequency decreasing first and then increasing.With the increase of doping amount,the symmetry of the six-membered ring composed of Zn(1)/Mg(1)O_(4)、Zn(2)/Mg(2)O_(4),and SiO_(4)tetrahedra increases,while the Zn(Mg)—O bond length decreases and the bond energy increases,resulting in the quality factor Q×f increases.Mg_(0.4)Zn_(1.4)Si O_(3.8) ceramicshave excellent properties,the relative permittivity ε_(r) is about 6.2,the Q×f is about 112 100 GHz,and the resonant frequency temperature coefficientτ_(f) is about-19.2×10^(-6)℃.

关 键 词：低介电常数 微波陶瓷 掺杂 晶体结构 微波性能 

分 类 号：TB34[一般工业技术—材料科学与工程]