Structure and Microwave Dielectric Properties of (Zn1−xCox)TiO3 Ceramics
Structure and Microwave Dielectric Properties of (Zn1−xCox)TiO3 Ceramics
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DOI：
10.1111/j.1151-2916.2003.tb03575.x
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发表时间：
2003-11
影响因子：
3.9
通讯作者：
Hyo Tae Kim;M. Lanagan
中科院分区：
文献类型：
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作者：
Hyo Tae Kim;M. Lanagan
采用固相反应法合成了（Zn 1-xCox）TiO 3（x= 0-1）系介电陶瓷。采用粉末X射线衍射分析、电子显微镜和微波测量技术对材料的相分布、微观结构和介电性能进行了表征。在1150°C下烧结的样品中鉴定出三个相组成区域; [尖晶石+金红石]在0 ≤x≤ 0.5处，[尖晶石+钛铁矿+金红石]在0.5 < x≤ 0.7处，以及[钛铁矿]相在0.7 < x≤ 1处。在0 ≤ x ≤ 0.5范围内，随着Co含量的增加，尖晶石相中的富Ti沉淀物数量减少，而金红石相数量增加。Co含量高时，出现钛铁矿相。微波介电性能取决于根据三相区域的相组成和体积，其中金红石与尖晶石或钛铁矿的相对量决定介电性能。采用麦克斯韦混合规则对介电常数作为Co添加量的函数进行建模。在介电常数为25，Q*f为70 000 GHz，谐振频率温度系数较低的情况下，确定了该系统的最佳相位分布。
Dielectric ceramics in the system (Zn1−xCox)TiO3 (x= 0–1) were synthesized by the solid-state reaction route. The phase distribution, microstructure, and dielectric properties were characterized by using powder X-ray diffraction analysis, electron microscopy, and microwave measurement techniques. Three phase composition regions were identified in the specimens sintered at 1150°C; [spinel + rutile] at 0 ≤x≤ 0.5, [spinel + ilmenite + rutile] at 0.5 < x≤ 0.7, and [ilmenite] phase at 0.7 < x≤ 1. For the 0 ≤x≤ 0.5 region, the amount of Ti-rich precipitates incorporated into the spinel phase decreased with the Co content at 0 ≤x≤ 0.5, with a concomitant increase of the rutile phase. The ilmenite phase appeared for high Co content. The microwave dielectric properties depended on the phase composition and volume according to the three phase regions, where the relative amount of rutile to the spinel or ilmenite determined the dielectric properties. The dielectric constant as a function of Co addition was modeled with a Maxwell mixing rule. An optimum phase distribution was determined in this system with dielectric constant of 25, a Q*f 70 000 GHz, and a low temperature coefficient of the resonant frequency.