JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·
IF 3.5
Xiaohui Wu,Xixi Wang,Yulan Jing,Yuanxun Li,Hua Su
With the emergence of 5G–6G communication technology, the miniaturization and integration of electronic components are crucial. Ba 3 Ti 4 Nb 4 O 21 (BTN) ceramics with hexagonal structures have attracted special attention due to their high dielectric constant, which shows greater application potential in communication base stations and dielectric resonators. However, its high sintering temperature and low-quality factors also greatly limit the application field. In this paper, boric acid (H 3 BO 3 ) as a dopant, was used to investigate the influence on the structure, microstructure, Raman spectrum, and microwave properties for Ba 2.92 Cu 0.08 (Zn 1/3 Nb 2/3 ) 2 Ti 2 Nb 4 O 21 (BCZTN)- x HB (0.25≤ x ≤1.25 wt%) ceramics. The results reflected that H 3 BO 3 was an effective additive, which could promote ceramic densification, accelerate grain growth and uniform distribution, and enhance its microwave performance. Among them, high densification was 93.92 ± 0.35%, and the Q × f value ∼16981 ± 340 GHz at x = 0.75, was more than 2∼3 times higher than other BTN-based ceramics. Superior microwave dielectric properties were achieved for 0.75 wt% H 3 BO 3 -doped BCZTN ceramic sintered at 900°C: ε r ∼42.35 ± 0.48, Q× f ∼16981 ± 340 GHz, and τ f ∼40.02 ± 1.43 ppm/°C. More encouragingly, BCZTN-0.75HB ceramic did not chemically react with Ag, which suggested that it had the potential to be a candidate material for low-temperature co-fired ceramics base station communication devices.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Xiaomeng Li,Xian Xue,Qiyin Lin,Zeming Qi,Hong Wang,Yingying Zhao,Jing Guo
Temperature stable xLi 2 MoO 4 -(1-x)(LiBi) 0.5 MoO 4 (x = 0, 40, 50, 60, 70, 100 vol%) microwave dielectric ceramics obtained by cold sintering process (CSP) under a mild sintering condition (120 ℃/30 min/200 MPa) are introduced in this work. The XRD , SEM, and Raman analysis indicate the coexistence of Li 2 MoO 4 and (LiBi) 0.5 MoO 4 phases. Li 2 MoO 4 -(LiBi) 0.5 MoO 4 ceramics are compatible with Ag and Al electrode materials under cold sintering condition. The specimens exhibit high relative densities and good microwave dielectric properties (relative permittivities: 31.5–5.5; Q×f values: 1900 - 18,500 GHz; TCF values: from +144 ppm/℃ to −106 ppm/℃), in particular, TCF = +0.7 ppm/℃ can be obtained in the case of x = 50 vol%. The extrapolated microwave dielectric properties obtained by the fitted infrared reflectivity spectrum are close to the measured data, revealing that the dielectric responses of cold sintered Li 2 MoO 4 -(LiBi) 0.5 MoO 4 ceramics in the microwave range are dominated by the polar optical phonons.
研究领域:
材料科学
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陶瓷
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微波工程
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固体物理
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Shuqun Wang,Hua Su,Fangyi Huang
In this work, two low-temperature co-fired silicate ceramics (CaMg 0.9- x Li 0.2 Co x Si 2 O 6 , x = 0.15–0.75, CMLCS; CaMg 0.9-y Li 0.2 Sr y Si 2 O 6 , y = 0, 0.05, 0.1–0.5, CMLSS) were synthesized via solid-state reaction method with 0.5 wt%LBSCA glass addition. CMLCS and CMLSS were densely sintered at 925 °C, and had good chemical compatibility with silver. Optimal microwave dielectric properties ( ε r = 6.71, Q×f = 30124 GHz, and τ f = −79.06 ppm/°C) and ( ε r = 6.78, Q×f = 32530 GHz, and τ f = −52.99 ppm/°C) were obtained for CMLC 0.15 S and CMLS 0.05 S respectively. With increase in Co and Sr substitution, XRD and Raman spectra showed that second phases were produced, and densification process of CaMgSi 2 O 6 -based ceramics was promoted. Dielectric constant was influenced by relative density, Raman shift and second phase. The parameter Q×f was affected by the FWHM of Raman peaks as well as extrinsic factors that affected the temperature coefficient of resonant frequency. Therefore, the results suggested the potential of these two ceramics as candidates for LTCC application.
研究领域:
材料科学
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电气工程
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陶瓷
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Weijia Guo,Zhiyu Ma,Yutian Lu,Zhenxing Yue
High- Q and temperature-stable ceramics are indispensable in microwave engineering. However, medium-permittivity ( ε r ∼ 60, named as K60) microwave dielectric ceramics that meet the above demands are yet to be synthesized. High- Q Ba 4 Sm 9.33 Ti 16.5 Al 2 O 54 (BSTA) and Ca 0.6 Sm 0.27 Ti 0.8 Al 0.27 O 3 (CSTA) ceramics have large resonant frequency temperature coefficients ( τ f ) with opposite signs. The composites of the two are expected to have good dielectric properties , but there will be obvious diffusion when they are compounded with each other by sintering after directly mixing the raw powder, which would lead to severe deterioration in dielectric properties. In this work, the undesired diffusion can be effectively avoided by stacking two or three ceramic layers together, which are achieved by two methods named adhesive bonding and spark-plasma-sintering (SPS) cofiring. The finite element method (FEM) analysis with COMSOL Multiphysics proposed in this work can precisely predict the microwave dielectric properties of layered ceramics, helping to determine the ratio of different layers to reach near-zero τ f . The adhesive-bonded layered ceramics exhibit excellent dielectric properties: ε r = 62.2, Q × f = 21,400 GHz, and τ f = –0.7 ppm/°C. The SPS-cofired layered ceramics can be fabricated in one time, partially solving the problem of sintering mismatch between different layers, together with superior properties of ε r = 59.8, Q × f = 19,780 GHz, and τ f = –0.6 ppm/°C. These layered ceramics could fill the gap of high- Q and temperature-stable K60 microwave dielectric ceramics. The layer-stacking process and related FEM simulations can be used to design more high- Q and temperature-stable microwave dielectric ceramics and devices.
研究领域:
材料科学
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陶瓷
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微波工程
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介电材料
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 107
·期 1
·223-233
·
IF 3.9
Zhenjun Qing,Huapeng Zou,Xin Zhou,Haiyan Li,An Liu,Shumin Duan,Yingxiang Li,Sen Peng
Li 2 Co 2 Mo 3 O 12 (LCMO) ceramics were synthesized using the solid-state reaction method. X-ray diffraction analysis results indicated that the sole crystalline phase present in the ceramics was LCMO, which belongs to the orthorhombic structure of the Pnma space group. The sample, which was sintered at 850°C, demonstrated outstanding microwave dielectric properties, with an ε r value of 8.95, a Q × f value of 43 200 GHz, and a τ f value of –71.3 ppm/°C. It was found that while the main factor influencing ε r was ionic polarizability, sintering density had a lesser effect on it. Furthermore, Q × f was primarily affected by relative density, and there was no significant relationship between packing fraction and this property. The higher the degree of distortion of the [Li/CoO 6 ] octahedron is, the poorer the τ f value of LCMO ceramics. Additionally, the microwave dielectric properties of LCMO ceramics were intrinsically linked to ionicity, lattice energy, bond energy, and thermal expansion coefficient of chemical bonds, with Mo–O bonds being the primary factor affecting these properties, as supported by analysis using chemical bonding theories. Mo–O bond vibration dominated the Raman spectra. Good chemical compatibility between silver and LCMO ceramics was demonstrated through our co-firing experiment.
研究领域:
材料科学
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陶瓷
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微波介质
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固态化学
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拉曼光谱
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·Vol. 51
·期 21
·34195-34202
·
IF 5.6
Zelai Cheng,Xi wang,Mingshan Qu,Xiuling Yang,Xian Jian,Hua Su
With the advent of fifth-generation technology, high-performance microwave dielectric materials with low dielectric constant are urgently needed to enable the miniaturization and integration of communication devices. This study presents the synthesis and characterization of a composite comprising SrCu 0.95 Mn 0.05 Si 4 O 10 (SCSMn) and Ba 3 V 2 O 8 (BV) ceramics, designed for LTCC applications. In a solid-state reaction method, the composition of the synthesized composite was tailored to adjust the τ f value and lower the sintering temperature . The results indicate that the composition of 47.5 wt% SCSMn and 52.5 wt% BV sintered at 925 °C exhibits optimal microwave dielectric properties , including ε r of 8.86, a Q × f of 33860 GHz, and a τ f of 3 ppm/°C. Microstructural analysis revealed that interionic diffusion during sintering induced amorphous phase formation and an increased concentration of defect-associated Cu + and V 5+ species. Concomitant modifications in bond valence summation (BVS) parameters and global instability index (GII) values within the composite ceramics were observed, which collectively account for the discrepancies between theoretical predictions and experimental dielectric properties . The composite material also demonstrated excellent impedance matching and radiation performance when utilized as a substrate for simulating a slot-coupled antenna, validating its promising potential for LTCC applications .
研究领域:
材料科学
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微波工程
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陶瓷与复合材料
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电子材料
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低温共烧陶瓷(LTCC)
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）