Structure and microwave dielectric properties of Ba3(VO4)2–Zn2−xSiO4−x ceramic composites
Structure and microwave dielectric properties of Ba3(VO4)2–Zn2−xSiO4−x ceramic composites
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DOI：
10.1016/j.materresbull.2013.02.014
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发表时间：
2013-06
影响因子：
5.4
通讯作者：
Yang Lv;R. Zuo;Zhenxing Yue
中科院分区：
文献类型：
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作者：
Yang Lv;R. Zuo;Zhenxing Yue
以Ba3(VO4)2和Zn1.87SiO3.87为原料，烧制了（1−y）Ba3(VO4) 2-yZn2−xSiO4−x（y=0.4 ~ 0.6, x=0.13）的微波介电陶瓷复合材料。x射线衍射（XRD）分析表明，适当控制氧化锌的缺乏量，可以得到具有钛矿相的zn2sio4。因此，在室温下，初始zn1.87 sio3.87粉末应由znsio4晶相和多余的sio2非晶相组成。扫描电镜研究表明，烧结体中存在zn2sio4和Ba3(VO4)2相共存，XRD和Raman结果进一步证实了这一点。由于两相的τf值相反，通过调整两相的相对含量可以获得谐振频率τf的近零温度系数。少量二次相的存在、元素间的相互扩散以及锌缺乏等非化学计量学因素共同导致了预测的性能值与实验测量值的偏差。在1100℃下烧结的40wt% zn1.87 sio3.87复合陶瓷具有良好的微波介电性能，质量因子Q×f ~ 23000 ghz，介电常数ε r ~ 9.3和τf ~ 0.4ppm/℃。
Microwave dielectric ceramic composites with compositions of (1−y)Ba3(VO4)2–yZn2−xSiO4−x(y=0.4–0.6, x=0.13) have been prepared by firing mixtures of Ba3(VO4)2and Zn1.87SiO3.87. The X-ray diffraction (XRD) analysis revealed that Zn2SiO4with a willemite phase can be obtained by appropriately controlling the ZnO deficiency. The starting Zn1.87SiO3.87powder should be thus composed of the ZnSiO4crystal phase and redundant SiO2amorphous phase at room temperature. The scanning electron microscopy studies demonstrated the coexistence of Zn2SiO4and Ba3(VO4)2phases in the sintered bodies, as further confirmed by the XRD and Raman results. The near-zero temperature coefficients of the resonant frequency (τf) could be achieved by adjusting the relative content of the two phases owing to their opposite τfvalues. The existence of a slight amount of secondary phases, element interdiffusion and non-stoichiometry such as Zn deficiency altogether made the predicted property values deviate from the experimentally measured ones. The composite ceramics with 40wt% Zn1.87SiO3.87sintered at 1100°C exhibited desirable microwave dielectric properties of the quality factor Q×f∼23,000GHz, dielectric constant ɛr∼9.3, and τf∼0.4ppm/°C.