Sintering behavior and microwave dielectric properties of Sr 2 CeO 4 ceramics doped with Li 2 CO 3 -Bi 2 O 3

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Sintering behavior and microwave dielectric properties of Sr2CeO4 ceramics doped with Li2CO3-Bi2O3 Fuming Zhou1, Hao Wang1, Jianming Guo1, Hui Yang1, LingFeng Li2, and Qilong Zhang1,*

1

School of Materials Science and Engineering, State Key Lab Silicon Mat, Zhejiang University, Hangzhou 310027, People’s Republic of China 2 Dongyang First Magnetics Co Ltd, Dongyang 322100, People’s Republic of China

Received: 31 August 2020

ABSTRACT

Accepted: 13 October 2020

Microwave dielectric ceramics Sr2CeO4 ? n wt% Li2CO3—Bi2O3 (LB) (1 B n B 4, L: B = x: y, weight ratio) were prepared by a traditional solid-state reaction method. The effects of LB additives on the phase formation, microstructure, sintering behavior, and microwave dielectric properties of Sr2CeO4 ceramics were investigated. The sintering temperature can be reduced obviously from 1270 to 950 °C because of the liquid phase formation of LB. Single-phase Sr2CeO4 ceramics with dense structure and homogenous grains were obtained by adding 1wt% LB. With LB content increasing, Q 9 f values would decrease because secondary-phase SrCeO3 appeared in the ceramics. When the content of LB was fixed at 1 wt%, the sintering temperature and Q 9 f value would decrease simultaneously with the ratio of Li2CO3 increasing. Desirable performances of Sr2CeO4 ? 1wt% LB ceramics: (er = 14.36, Q 9 f = 102,023 GHz and sf = - 66.42 ppm/°C, L:B = 2:8) and (er = 13.56, Q 9 f = 70,109 GHz, sf= - 64.17 ppm/°C, L:B = 8:2) can be achieved at 1075 °C and 950 °C, respectively, suggesting that Sr2CeO4–LB ceramics have a great potential for millimeter-wave applications.

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Springer Science+Business

Media, LLC, part of Springer Nature 2020

1 Introduction In recent years, with the rapid development of 5G communication, the Internet of Things and Intelligent Transport Systems which require a high-throughput, higher specifications such as faster communication speed and signals with better qualities are urgently needed for the new communication technologies. Thus, there is a sharp increase in demands for novel

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https://doi.org/10.1007/s10854-020-04682-z

microwave dielectric ceramics materials used for high frequency bands. In general, materials with high permittivity are frequently used for the minimization of devices and low-permittivity materials are commonly for fast-speed communication. Ceramics with low permittivities (er \ 20) are common in the millimeter-wave communication, which can offer signal transmission with high speed for fifth generation communication systems. In addition, high quality

J Mater Sci: Mater Electron

factor is also important for microwave dielectric ceramics [1–4]. Up to now, many microwave dielectric ceramics with low er and high Q 9 f values have already been researched. Such as, MgTiO3, Mg2SiO4, Ca2SnO4, Li2Mg3BO6 (B = Ti, Sn, Zr) ceramics, etc. [5–11]. Recently, Sr2CeO4 ceramics have been researched as a novel microwave dielectric material. The orthorhombic Sr2CeO4 ceramic is one of the universal luminescent