Structure, morphology, and microwave dielectric properties of SmAlO 3 synthesized by stearic acid route
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ISSN 2226-4108 CN 10-1154/TQ
Research Article
Structure, morphology, and microwave dielectric properties of SmAlO3 synthesized by stearic acid route Jiamao LIa,b,*, Chuimin ZHANGa, Hui LIUa, Tai QIUc, Chuangang FANa,* a
b
School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243032, China Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials, Ministry of Education, Anhui University of Technology, Maanshan 243002, China c College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China Received: April 1, 2020; Revised: May 30, 2020; Accepted: June 2, 2020 © The Author(s) 2020.
Abstract: A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through the combustion of stearic acid precursors. The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to analyze the phase composition and microstructure. The dielectric characteristics of SmAlO3 microwave ceramics, using the as-obtained products as original materials, were also studied. Compared with the conventional solid-state reaction method, the synthesis temperature was dramatically reduced to 750 ℃. The large-size sheet structure was composed of a number of micro/nano-scale crystallites, which were mostly irregular in shape due to the mutual growth and overlapping shapes of adjacent grains. The SmAlO3 ceramics with high density and uniform microstructure were obtained after sintering at 1500 ℃ for 4 h due to the favorable sintering activity of the as-synthesized powders. In addition, desired dielectric properties at microwave frequencies (dielectric constant εr = 20.22, quality factor Q·f = 74110 GHz, and a temperature coefficient of resonant frequency τf = –74.6 ppm/℃) were achieved. Keywords: stearic acid precursor process; nanoparticle; perovskite; microwave ceramics
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Introduction
In the high-frequency region, microwave dielectric ceramics are regarded as suitable materials for application in modern communication systems because they exhibit good properties such as high εr, high Q·f, and near-zero τf [1–4]. Rare-earth aluminate ceramics with perovskite * Corresponding authors. E-mail: J. Li, [email protected]; C. Fan, [email protected]
structure are an example of such materials, and therefore have attracted a great deal of interest in recent decades. Cho et al. [5] reported the εr and Q·f values of 20.4 and 65000 GHz for SmAlO3 ceramics respectively, prepared by solid-state reaction method, indicating a potential application in wireless communication as dielectric resonators, filters as well as dielectric antenna. High dielectric constant and Q·f can miniaturize the size and ensure a favorable frequency selectivity in these microwave devices, respectively. SmAlO3 can also find an extensive application in superconduc
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