Microwave dielectric properties of low-fired Li 2 Mg 3 TiO 6 nanocrystalline ceramics derived from ultrafine particles
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Microwave dielectric properties of low-fired Li2Mg3TiO6 nanocrystalline ceramics derived from ultrafine particles Jianli Ma1, Qing Cheng1, Zhifen Fu1,*
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, Zhongyi Yang1, Simei Zhai2, and Peng Liu2
School of Mechanics and Optoelectronic physics, Anhui University of Science and Technology, 232001 Huainan, China College of Physics and Information Technology, Shaanxi Normal University, 710062 Xi’an, China
Received: 23 April 2020
ABSTRACT
Accepted: 29 September 2020
Li2Mg3TiO6 nanopowders were prepared using the High-Energy Ball Milling (HEBM) method. The nanopowders were used for the development of a nanocrystalline ceramic. A pure Li2Mg3TiO6 cubic phase was synthesized at 800 °C with an average grain size of 420 nm. Using ultrafine particles as a precursor, a highly dense Li2Mg3TiO6-based ceramic was obtained at the range of 1000–1100 °C with a relative density of approximately 96%. At 950–1050 °C, the average grain size varied from 200 nm to 1000 nm and the Q 9 f values increased from 20,100 GHz to 106,170 GHz. Q 9 f values of Li2Mg3TiO6 ceramic strongly depended on the grain size as well as the packing fraction.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
1 Introduction Development in the miniaturization of multifunctional devices, microwave circuitry, and other systems has attracted considerable attention. One of the reasons is the lightweight of the miniaturized product. The multilayered components of chips are fabricated based on multi-layer circuit design and lowtemperature co-fired ceramics (LTCC) technology. Not only the circuit density but also the reliability of the system was improved [1, 2]. In order to ensure uniform quality, micrometer-scale dielectric layers are generally required that are at least 20–30 layers thick. Therefore, nano-sized grains are demanded for the fabrication of certain types of ceramics. The
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https://doi.org/10.1007/s10854-020-04563-5
preparation of low-fired nanocrystalline ceramics is still a challenge, although several techniques have been proposed [3–5]. High-energy ball milling (HEBM) has been used to prepare nano-sized powders due to its ability to enhance the sintering kinetics [6, 7]. Recently, rock salt structure Li2Mg3TiO6 ceramics has been generated with considerable interest because of its excellent dielectric properties: er = 15.2, Q 9 f = 152,000 GHz, and sf = - 39 ppm/°C [8]. Studies have been conducted to improve the sintering behavior and microwave dielectric properties of Li2Mg3TiO6-based ceramics [9]. The sintering temperatures of Li2Mg3TiO6-based ceramics were reduced to a range of 950–1050 °C by doping LiF and glass
J Mater Sci: Mater Electron
agents [10–12]. Its sf value was modified by compositing with Ca0.8Sr0.2TiO3 and SrTiO3 [13, 14]. The grain size distribution of Li2Mg3TiO6-based ceramics fabricated via a conventional solid-state method is generally within the micron scale. This is because a coarse powder was used as its starting material, which possess a low
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