Modeling for high-temperature dielectric behavior of multilayer C_f/Si₃N₄ composites in X-band

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• 作者：Heng Luo^a ; ^b ; Yongqiang Tan^a ; Yang Li^b ; ^c ; Peng Xiao^b ; ^{xiaopengcsu@csu.edu.cn} ; Lianwen Deng^b ; Sifan Zeng^a ; Guojun Zhang^d ; ^e ; Haibin Zhang^a ; ^{hbzhang@caep.cn} ; Xiaosong Zhou^a ; Shuming Peng^a ; ^{pengshuming@caep.cn}
• 关键词：High-temperature dielectric ; Multilayer Cf/Si3N4 ; Relaxation time
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：May 2017
• 年：2017
• 卷：37
• 期：5
• 页码：1961-1968
• 全文大小：2404 K
• 卷排序：37

文摘

The high-temperature dielectric behavior of multilayer Cf/Si3N4 composites fabricated by gelcasting and pressuureless sintering was intensively investigated at temperatures coverage up to 800 °C in X-band (8.2–12.4 GHz). Experimental results have shown the permittivity of Si3N4 matrix exhibits excellent thermo-stability with temperature coefficient lower than 10−3 °C−1. Besides, both the real and imaginary parts of permittivity of multilayer Cf/Si3N4 composites exhibit positive temperature coefficient characteristic which attributed to the enhancement of space charge polarization. Furthermore, temperature-dependent permittivity of Cf/Si3N4 composites is demonstrated to be well distributed on circular arcs with centers actually keep around the real (ε'ε') axis in Cole-Cole plane. Finally, the relaxation time for multilayer Cf/Si3N4 composites gradually increases from 216.1 ps to 250.2 ps when heated from room temperature to 800 °C, and is almost twice as much as a single cycle for electromagnetic wave in X-band which leads to continuous decrease in permittivity with frequency.