Ba基复合钙钛矿微波介质陶瓷的晶格振动光谱及结构性能关系研究

发布时间：2018-07-04 19:59

本文选题：微波介质陶瓷 + 拉曼光谱　；参考：《山东师范大学》2015年硕士论文

【摘要】：微波介质陶瓷是微波频段（300MHz-30GHz）电路中的重要材料之一。因为微波器件信息容量大，方向性和穿透性强的特点，成为微波电容器、介质天线等元器件的核心材料。随着现在移动通讯技术对设备小型化和高频化的要求，探索高介电常数，高品质因数，低损耗以及低成本的微波介质陶瓷材料成为近年来炙手可热的研究焦点。 A(B1/2B1/2)O3和A(B1/3B2/3)O3型陶瓷在现实生活中的应用有着很不错的发展前景。它们本身具有特殊的结构特征和原子排列方式，使它们在微波和毫米介电响应方面有着出色的表现。而这种优势和它们的光子振动特性息息相关，样品制备条件对光子特性的研究同时也有着重要影响。因此，，通过对微观结构的研究，可以探索新工艺新配方下的陶瓷的性能优劣，为实现新型陶瓷的大批量应用奠定基础。本文采用固相合成法制备了Ba(Zn1/3Nb2/3)O3-xCaTiO（3BZN-CT，x=0.0，0.30，0.60，0.75，0.90）和(1-x)Ba(Mg1/3Ta2/3)O3-xBa(Co1/3Nb2/3)O3（BMT-BCN，x=0.0，0.20，0.25，0.30，0.40）微波介质陶瓷。通过不同的数据处理方式对XRD衍射，Raman散射以及FTIR反射光谱测试数据进行处理和整理，同时与所测得的样品的介电性能联系起来进行比对和研究。讨论了BZN-CT陶瓷晶体结构随着A位Ca2+和B位Ti4+的取代而发生的变化与振动模式和结构性能之间的关系以及B位Co2+和Nb5+取代对BMT-BCN陶瓷晶体微观结构和性能的影响。1. Ba(Zn1/3Nb2/3)O3-xCaTiO3陶瓷晶格振动光谱与结构性能总结 1)将XRD数据与JCPDS卡片进行比对，得到纯的BZN陶瓷为立方有序结构，系统的晶格对称性随CaTiO3添加组分的增大而降低，从开始的立方相在x=0.60时由赝立方相向六方相转变，有序结构由BZN的1:1有序向1:2有序转变； 2)在拉曼光谱中，与1:2有序结构相关的A1g(Nb)振动模在x=0.60处突然向高频偏移，同时，F2g(O)振动模由于长程1:2有序的存在而发生了分裂； 3) F2g(O)振动模的半高宽的变化与损耗tan相同，与介电常数r相反，分别在x=0.60时达到最小值和最大值，而温度系数却与Eg(O)的拉曼位移变化一致，这说明在CaTiO3的掺杂量为60㳠时，BZN-CT陶瓷的介电性能达到最佳； 4)通过群论分析完成对红外光谱的指认，讨论了在x≥0.60时300cm1和600cm1附近出现的新模式以及介电常数虚部中强度变化的分析和峰值频率与介电性能的研究。2.(1-x)Ba(Mg1/3Ta2/3)O3-xBa(Co1/3Nb2/3)O3陶瓷晶格振动光谱与结构性能总结 1)通过JCPDS卡片与XRD测试数据比对，BMT-BCN固溶体样品被确定为六方有序结构，且随着Ba(Co1/3Nb2/3)O3掺杂量的增加，该体系的晶格对称性降低，有序度也随之降低。 2)拉曼光谱中，Eg(O)振动模的半高宽与介电常数r在x≤0.25成正相关，而在x≥0.25呈逆相关；损耗tan与F2g(O)和A1g(O)振动模式的半高宽在x≤0.25呈逆相关，在x≥0.25成正相关，容量温度系数呈非线性变化，这均证明了在x=0.25时，BMT-BCN陶瓷固溶体的晶体结构与介电性能达到最优。 3)完成红外光谱的指认，得出x=0.25的BMT-BCN陶瓷的红外光谱强度突然变小，其中一些振动模式甚至消失，最终得到此组分下的样品具有更好的介电性能，证实了XRD以及拉曼研究结论的正确性。
[Abstract]:Microwave dielectric ceramics are one of the important materials in the microwave band (300MHz-30GHz) circuit. Because of the characteristics of high information capacity, direction and penetration, microwave devices have become the core materials of microwave capacitors, dielectric antennas and other components. With the requirements of miniaturization and high frequency of mobile communication technology, the high permittivity is explored. High quality factor, low loss and low cost microwave dielectric ceramic materials have become a hot research focus in recent years.
The application of A (B1/2B1/2) O3 and A (B1/3B2/3) O3 ceramics in real life has a very good prospect. They have special structural characteristics and atomic arrangement, which make them excellent in microwave and millimeter dielectric response. This advantage is closely related to their photon vibration characteristics, and the sample preparation strips are closely related. The research on the properties of the photons also has an important influence. Therefore, through the study of the microstructure, we can explore the performance and quality of the ceramics under the new technology and new formula, which lays the foundation for the realization of the large batch application of the new type of ceramics.
In this paper, Ba (Zn1/3Nb2/3) O3-xCaTiO (3BZN-CT, x=0.0,0.30,0.60,0.75,0.90) and (1-x) Ba (Mg1/3Ta2/3) O3-xBa (Co1/3Nb2/3) O3 (Co1/3Nb2/3) O3 microwave dielectric ceramics were prepared by solid phase synthesis. The relationship between the crystal structure of BZN-CT ceramics with the substitution of A bit Ca2+ and B bit Ti4+ and the relationship between the vibration mode and the structure and properties, and the effect of B bit Co2+ and Nb5+ on the microstructure and properties of the BMT-BCN ceramics crystal are discussed. The.1. Ba (Zn1) (Zn1) (Zn1) is considered as the.1. Ba (Zn1). Vibrational spectra and structural properties of /3Nb2/3) O3-xCaTiO3 ceramics
1) comparing the XRD data with the JCPDS card, the pure BZN ceramic is a cubic ordered structure. The lattice symmetry of the system decreases with the increase of the added component of the CaTiO3. The cubic phase from the beginning is transformed from the pseudo cubic phase to the six square phase, and the ordered structure transforms from the 1:1 order of BZN to the 1:2 orderly.
2) in the Raman spectrum, the A1g (Nb) vibration mode related to the ordered structure of 1:2 suddenly shifts to high frequency at x=0.60, while the F2g (O) vibration mode is split due to the existence of the long range 1:2 order.
3) the half width of the F2g (O) vibration mode is the same as that of the loss tan. Contrary to the dielectric constant R, the minimum and maximum values are reached at x=0.60, while the temperature coefficient is the same as that of the Eg (O). This shows that the dielectric properties of the BZN-CT ceramics are best when the amount of doping is 60?
4) the identification of infrared spectra is completed by group theory analysis. The new modes of 300cm1 and 600cm1 at x > 0.60 and the analysis of the intensity changes in the imaginary part of the dielectric constant and the study of the peak frequency and dielectric properties of the dielectric constant are discussed. The lattice vibration spectra and the structural properties of the.2. (1-x) Ba (Mg1/3Ta2/3) O3-xBa (Co1/3Nb2/3) O3 ceramics are summarized.
1) by comparing the JCPDS card with the XRD test data, the BMT-BCN solid solution sample is determined to be an ordered structure of six square, and with the increase of Ba (Co1/3Nb2/3) O3 doping, the lattice symmetry of the system decreases and the order degree decreases.
2) in the Raman spectrum, the half width of the Eg (O) vibration mode and the dielectric constant R are positively correlated with the x < 0.25, but the x > 0.25 is inverse correlation; the half width of the loss Tan and F2g (O) and A1g (O) vibration mode is inverse correlation to x < 0.25, and the capacity temperature coefficient is nonlinear. The crystal structure and dielectric properties are optimal.
3) completing the identification of infrared spectra, it is concluded that the infrared spectral intensity of x=0.25 BMT-BCN ceramics suddenly becomes smaller, and some of the vibration modes even disappear. Finally, the samples under this component have better dielectric properties, and the correctness of the XRD and Raman results is confirmed.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1

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