Sintering characteristics and microwave dielectric properties of a new temperature-stable ceramic of Ce 0.5 Sm 0.5 O 1.7
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Sintering characteristics and microwave dielectric properties of a new temperature-stable ceramic of Ce0.5Sm0.5O1.75 Ying Wang1,* , Tian-Liang Tang1, Jing-Yu Deng1, Ming-Xue Li1, Li-Wei Shi1, and Wang-Suo Xia1 1
School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
Received: 16 April 2020
ABSTRACT
Accepted: 6 September 2020
The novel temperature-stable microwave dielectric ceramics of Ce0.5Sm0.5O1.75 were fabricated via the mixed oxide reaction method, with the detail information including crystal phase, microstructure, sintering behavior and microwave dielectric properties being systematically investigated. For crystal phase, all the diffraction patterns were indexed as cubic fluorite-type structure with Fm-3m (225) space group and exhibited a single phase with no obvious peak position shift. The grain growth was analyzed by density and average grain size. For microwave dielectric properties of Ce0.5Sm0.5O1.75 ceramics, the dielectric constant value (er) was dependent on density. The quality factors (Q 9 f values) were investigated considered with average grain size. And the temperature coefficient of resonant frequency (sf value) had no significant change during the sintering temperature range, which was found consistent with the trend of the dielectric constant value. The Ce0.5Sm0.5O1.75 ceramics sintered at 1475 °C for 4 h exhibited good microwave dielectric performances with er = 18.21, Q 9 f = 70,500 GHz, and sf = - 16.4 ppm/°C.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
1 Introduction During recent years, microwave dielectric ceramics of cerium oxide (CeO2), which belong to the cubic fluorite structure, with a dielectric constant of 24, quality factor of 57,000 GHz and temperature coefficient of resonant frequency of - 104 ppm/°C, have attracted much more attention [1]. According to previous study, CeO2 was usually selected as an effective additive to optimize microwave dielectric
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https://doi.org/10.1007/s10854-020-04449-6
properties. For examples, Wang et al. reported that 0.6LaGaO3–0.4SrTiO3 compounds presented better microwave dielectric properties with 0.05% CeO2 addition: er = 32.9, Q 9 f = 62,150 GHz and sf = - 26.6 ppm/°C [2]. Fang et al. reported that the Na1/2Sm1/2O3 ceramics showed excellent microwave dielectric properties (er = 103.01, Q 9 f = 9640 GHz and sf = 192.8 ppm/°C) by adding 0.5 wt% CeO2 [3]. However, when it comes to optimization of microwave dielectric properties for CeO2 ceramics, few
J Mater Sci: Mater Electron
researches can be found. Moreover, it is noticeable that if the sf values have been optimized, the ceramics will have excellent microwave dielectric properties for application. In 2003, the effects of Sm2O3 on pure CeO2 ceramics about crystal structure transformation were investigated [4]. Based on the inspiration of that report, in this paper, the Ce0.5Sm0.5O1.75 ceramics were designed and synthesized by the traditional solidstate sin
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