Phase Evolution, Microstructure and Microwave Dielectric Properties of Zn1.9-2xLixAlxSi1.05O4 Ceramics |
Yun-Han Kim, Shin Kim1, Seong-Min Jeong2, So-Jung Kim3, Sang-Ok Yoon |
Department of Materials Engineering, Graduate School, Gangneung-Wonju National University 1Hasla Co., Ltd. 2Energy & Environmental Division, Korea Institute of Ceramic Engineering and Technology(KICET) 3Department of Electrical and Electronic Engineering, Hanzhong University |
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ABSTRACT |
Phase evolution, microstructure, and microwave dielectric properties of $Li_2O$ and $Al_2O_3$ doped $Zn_{1.9}Si_{1.05}O_4$, i.e., $Zn_{1.9-2x}Li_xAl_x-Si_{1.05}O_4$, ceramics (x = 0.02 ~ 0.10) were investigated. The ceramics were densified by $SiO_2$-rich liquid phase composed of the Li-Al-Si-O system, indicating that doped Li and Al contributed to the formation of the liquid. As the secondary phase, ${beta}$-spodumene solid solution with the composition of $LiAlSi_3O_8$ was precipitated from the liquid during the cooling process. The dense ceramics were obtained for the specimens of $$x{geq_-}0.06$$ showing the rapid densification above $1000^{circ}C$, implying that a certain amount of liquid is necessary to densify. The specimen of x = 0.06 sintered at $1050^{circ}C$ exhibited good microwave dielectric properties; the dielectric constant and the quality factor ($Q{times}f_0$) were 6.4 and 11,213 GHz, respectively. |
Key words:
$Zn_2SiO_4$, Liquid-phase sintering, $LiAlSi_3O_8$, Dielectric constant, Quality factor |
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