Phase evolution,crystal structure,and microwave dielectric properties of gillespite-type ceramics |
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Authors: | Xiao-Qiang Song Wen Lei Fei Wang Tao Chen Shi-Wo Ta Zhen-Xiao Fu Wen-Zhong Lu |
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Affiliation: | 1. School of Optical and Electronic Information, Key Lab of Functional Materials for Electronic Information (B) of MOE, Huazhong University of Science and Technology, Wuhan, P. R. China;2. State Key Laboratory of Advanced Materials and Electronic Components, Guangdong Fenghua Advanced Technology Holding Co., Ltd., Zhaoqing, P. R. China |
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Abstract: | A gillespite-structured MCuSi4O10 (M = Ba1-xSrx, Sr1-xCax) ceramics with tetrahedral structure (P4/ncc) were prepared by solid-state reaction method. X-ray diffraction and thermogravimetry with differential scanning calorimetry (TG-DSC) were employed to study the phase synthesis process of BaCuSi4O10. Pure BaCuSi4O10 phase was obtained at 1075°C and decomposed into BaSiO3, BaCuSi2O6, and SiO2 when calcined at 1200°C. The relationships between the crystal structure and microwave dielectric properties of MCuSi4O10 ceramics were revealed based on the Rietveld refinement and P-V-L complex chemical bond theory. The dielectric constant (εr) decreased linearly with decreasing total bond susceptibility and ionic polarizability. Quality factor (Q × f) was closely dependent on bond strength and lattice energy. The temperature coefficient of resonant frequency (τf) was controlled by the stability of CuO4]6? plane in MCuSi4O10. Optimum microwave dielectric properties were obtained for SrCuSi4O10 when sintered at 1100°C for 3 hours with a εr of 5.59, a Q × f value of 82 252 GHz, and a τf of ?41.34 ppm/°C. Thus, SrCuSi4O10 is a good candidate for millimeter-wave devices. |
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Keywords: | BaCuSi4O10 gillespite microwave dielectric properties |
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