A位取代对ZnO-0．5SiO2陶瓷烧结特性和介电性能的影响

Effect of A-site Substitution on Sintering and Dielectric Properties of ZnO-0.5SiO_2 Ceramics

采用常规固相反应法,以ZnO-0.5Si O2体系为基体成分,研究了A位取代ZnO-0.5Si O2陶瓷的烧结特性和介电性能的影响规律.结果表明:Mg在一定范围内A位取代ZnO-0.5Si O2中的Zn可形成(Zn1-x,Mgx)2Si O4固溶体,x(Mg)最大固溶度不超过0.5.当取代量超过固溶度后,出现Mg2Si O4和Mg2Si O3相.x(Mg)≤0.5,陶瓷介电常数变化不大,品质因子较高;x(Mg)>0.5时,陶瓷介电常数增大,品质因子急剧下降.研究还揭示了(Zn1-x,Mgx)2Si O4(x=0.1~0.3)陶瓷在1 275℃烧结具有良好的介电性能,其介电常数为6.19~6.23,品质因子为48 000~53 000 GHz,频率温度系数为-50×10-6^-60×10-6/℃.

The ZnO-0.5SiO2 ceramics were prepared by conventional solid oxide process method, For the ZnO-0.5SiO2 system, the effect of A-site substitution on sintering and dielectric properties was systematically investigated. According to the XRD analysis,it was found that the maximum solubility of Mg^2＋ is 0.5 ： when the solubility, x（Mg）, is lower than 0.5, the （Zn1-x, Mgx）2 SiO4 phase formed in the ceramics;but if the solubility is higher than 0.50,the second phases of Mg2SiO4 and Mg2SiO3 formed in the system. Thus,it is reasonable to deduce that the solubility limitation has a significant influence on the formation of the phases in the ceramics. The influence of the x（Mg） value on the microstructure property of the ceramics was revealed by the SEM observation. The decrease of the sintering temperature was explained by considering the introduction of the Mg^2＋ , which led to the distortion of the crystal lattice or the formation of defects in the ceramics. For x（Mg）≤0.5, the dielectric constant varied a little and the quality factor shown higher values. For x（Mg）〉0. 5, the dielectric constant increased but the quality factor decreased sharply. It was verified that the （Zn1-x, Mgx）2 SiO4 （x = 0.1 - 0.3） ceramics sintered at 1 275℃ exhibited good microwave dielectric properties; the dielectric constant,the quality factor and the temperature coefficient of resonant frequency are 6.19-6.23,48 000-53 000 GHz and -50 × 10^-6 - - 60 ×10^-6/℃, respectively .