JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Sijie Wang,Weishuang Fang,Daofu Wu,Kuiyi Meng,Ying Tang,Junfeng Yang,Mingjian Ding,Huixing Lin,Liang Fang
K20 microwave dielectric ceramics SrLnAlO 4 (Ln = Eu, Gd, and Ho) were prepared at 1440–1520 °C. SrEuAlO 4 and SrGdAlO 4 crystallized into tetragonal K 2 NiF 4 -type structures. While SrHoAlO 4 was a mixture (SrHo 2 Al 2 O 7 , Ho 2 O 3 , and Sr 3 HoAl 2 O 7.5 ) due to the too-small radius of Ho 3+ to bond in [HoO 9 ] dodecahedron . SrEuAlO 4 and SrGdAlO 4 exhibited near-zero τ f values of +1.7 and +4.3 ppm/°C and low ε r (19.37 and 19.14) along with contrasting Q × f values (70,030 and 5560 GHz). Compared with the modified molecular polarizability ( α Corr ) based on the bond valence deviation, the α obs values of SrEuAlO 4 and SrGdAlO 4 are much higher, indicating that their dielectric polarizabilities were underestimated, and this phenomenon was mainly influenced by rattling cations, which also causes their τ f with near-zero values. Due to the magnetic subsystem adversely affecting microwave dielectric losses , the worsened Q × f value of SrGdAlO 4 compared to that of SrEuAlO 4 is due to the high magnetic moment of Gd 3+ (7.94 μ B ).
研究领域:
材料科学
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电子工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Sen Peng,Lei Xiao,Yingxiang Li,Lianwen Deng,Jiahui Zhu,Zhenjun Qing,Yecheng Xi
A novel Ba 3 (ZnB 5 O 10 )PO 4 (BZBPO) phosphate ceramic was synthesised using a conventional solid-state technology. The BZBPO ceramic sintered at 850 °C demonstrated exceptional microwave dielectric properties : ε r = 5.88 ± 0.08, Q×f = 52,896 ± 1200 GHz ( f 0 = 16.5 GHz) and τ f = 0.34 ± 0.25 ppm/°C. Raman spectroscopy revealed that ε r and Q×f were negatively correlated with the Raman shift and full width at half maximum of the BZBPO ceramic, respectively. Meanwhile, Phillips–Vechten–Levine theory revealed that Q×f was highly correlated with the lattice energy ( U b ), and τ f was closely related to the bond energy ( E b ) and the thermal expansion coefficient. Among contribution ratios of individual chemical bonds, the B–O bond mainly contributed to U b , E b and ionicity, proving that the bond dominantly affected the dielectric properties of the BZBPO ceramic. Finally, the BZBPO ceramic was co-fired with silver, demonstrating its potential applicability towards low temperature co-fired ceramic technology.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Caidan Hou,Zhuo Wang,Jinteng Kang,Ying Xue,Zhuang Liu,Zeyu Ning,Junke Xie,Xin Li
The microwave dielectric properties of SrLa₂Al₂O₇ ceramic, specifically the quality factor ( Qf ) and temperature coefficient of resonant frequency ( τ f ), were enhanced through substituting La 3+ with Sr 2+ at the A-site and Al 3+ with Ti 4+ at the B-site. Pure-phase Sr/Ti co-substituted Sr 1+2 x La 2−2 x Al 2−2 x Ti 2 x O 7 ceramics were synthesized via solid-phase reaction route. Remarkably, at an optimal substitution level of x = 0.55, the resulting Sr 2.1 La 0.9 Al 0.9 Ti 1.1 O 7 ceramic exhibited superior microwave dielectric properties: ε r = 25.94 ± 0.32, Qf = 117,300 ± 5700 GHz ( f 0 = 6.40 GHz), τ f = 3.28 ± 0.17 ppm/°C. The increase of Qf value was highly associated with the low interlayer polarization effect caused by the small absolute value of interlayer polarization charges. The τ f value was jointly dominated by both τ ε and the bond valence of B-site bonds.
研究领域:
材料科学
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电子材料
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DOI
高影响因子
INORGANIC CHEMISTRY
·
2019
·
IF 4.85
Xiaoyan Yang,Tashtanbekova Kyzzhibek,Cécile Genevois,Weiwei Cao,Florence Porcher,Xiaojun Kuang,Mathieu Allix
Highly positive temperature coefficients of the resonant frequency (τf) of eight-layer hexagonal perovskites are hardly tunable, hindering their application as microwave dielectric resonators. Here, we show that a near-zero τf (∼0.48 ppm °C–1) can be achieved on eight-layer shifted hexagonal perovskite Ba8CoNb4Ta2O24, along with a permittivity εr of ∼30.6 and a Qf of ∼36400 GHz, through substitution of Ta for Nb, satisfying the resonator application requirement. The decrease in the τf of Ba8CoNb6–xTaxO24 takes place mainly through the decrease in the εr or temperature coefficient of permittivity, owing to the less covalent bonding and lower polarizability of Ta5+ compared to those of Nb5+. Synchrotron and neutron powder diffraction data, scanning transmission electron microscopy–high-angle annular dark field imaging, and atomic-scale X-ray energy dispersive spectroscopy elemental mapping reveal that Ta5+ cations in Ba8CoNb4Ta2O24 are naturally distributed in a partially ordered manner, showing a strong site preference on the Nb layers close to the central Co layer over the most out-of-center distorted Nb layers next to empty octahedral layers. This spontaneous Ta ordering in the niobate host is driven by different covalent bonding nature and second-order Jahn–Teller distortion extents of Ta5+ and Nb5+. The results demonstrate an effective way of substituting more ionic Ta5+ for Nb5+, which decreases the τf to near-zero values for eight-layer hexagonal perovskite niobate dielectrics.
研究领域:
材料科学
·
固态物理
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电子材料
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DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2025
·Vol. 51
·期 30
·65060-65066
·
IF 5.6
Hui Yan,Yue Ma,Yong Shang,Yun Wang,Kaixin Song,Guoda Xie,Bo Wu,Xingang Ren,Xianliang Wu,Gang Wang
A series of novel low-permittivity microwave dielectric ceramics with the compositions of (1- x ) BaY 2 Si 3 O 10 - x Ba 5 Si 8 O 21 (0.3 ≤ x ≤ 0.7) and 0.4 BaY 2 Si 3 O 10 -0.6 Ba 5 Si 8 O 21 - y wt% LiF (1 ≤ y ≤ 3) were successfully synthesized using solid-state reaction sintering. The phase evolution and microwave dielectric properties of these ceramics were systematically studied. X-ray diffraction analysis indicated the coexistence of BaY 2 Si 3 O 10 and Ba 5 Si 8 O 21 phases in the (1- x ) BaY 2 Si 3 O 10 - x Ba 5 Si 8 O 21 system, with no secondary phases detected. In contrast, an additional Ba 2 Si 3 O 8 phase was identified in the LiF-modified composition (0.4 BaY 2 Si 3 O 10 -0.6 Ba 5 Si 8 O 21 - y wt% LiF (1 ≤ y ≤ 3)). Moreover, the Ba 5 Si 8 O 21 phase was found to effectively tune the temperature coefficient of resonant frequency (τ f ) to near-zero values in both systems. Excellent microwave dielectric properties were obtained for the 0.4 BaY 2 Si 3 O 10 -0.6 Ba 5 Si 8 O 21 - 2 wt% LiF ceramic, exhibiting a permittivity ( ε r ) of 7.45, a quality factor ( Q × f ) of 13,152 GHz, and a τ f value of −3.17 ppm/°C. This composition also showed good chemical compatibility with silver electrodes, suggesting its potential for use in low-temperature co-fired ceramic (LTCC) applications.
研究领域:
材料科学
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陶瓷
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微波介质材料
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电子材料
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低温共烧陶瓷（LTCC）技术
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Mingxin Liu,Jie Li,Ying Tang,Junqi Chen,Laiyuan Ao,Alin Cao,Liang Fang
The τ f of Y 3 Ga 5 O 12 ceramics was adjusted by Ca 2+ /Ti 4+ co-doping for Y 3+ at A-site and Ga 3+ at C-site to form Ca x Y 3- x Ti x Ga 5- x O 12 (0 ≤ x ≤ 2.0) ceramics by the solid-state reaction. When 0 ≤ x ≤ 1.7, all the samples remained as single garnet-structured with Ia- 3 d space group. The ε r increased from 10.4 ± 0.1 to 15.9 ± 0.1, and τ f optimized from −54.7 ± 1.0 to −8.3 ± 1.0 ppm/℃, attributing to the increase in polarizability per volume and “rattling” effect. Meanwhile, the Q × f slightly decreased from 98,200 ± 500 GHz to 65,300 ± 500 GHz due to the decrease in packing fraction. As x increased to 2.0, the properties dramatically deteriorated owing to the second phase CaTiO 3 . Optimal properties were obtained at x = 1.7, with ε r = 15.9 ± 0.1, Q × f = 65,300 ± 500 GHz and τ f = −8.3 ± 1.0 ppm/℃.
研究领域:
材料科学
·
电子材料
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
IF 2.39
C.X. Chen,S.P. Wu,Y.X. Fan
Orthorhombic Mg 2 GeO 4 ceramics were synthesized by solid-state reaction method. When stoichiometric compositions were employed, the phase transition produced under low temperature and pure orthorhombic Mg 2 GeO 4 phase appeared at 1000 °C. B 2 O 3 was employed as sintering aid to lower the sintering temperature of Mg 2 GeO 4 ceramics and improve their relative densities. The B 2 O 3 -doped Mg 2 GeO 4 ceramics have a low sintering temperature of 1250 °C and a small negative τ f value. Microwave dielectric properties of B 2 O 3 -doped Mg 2 GeO 4 ceramics were: ε r = 6.76, Q × f = 95,000 GHz and τ f = −28.7 ppm/°C. They could be considered as promising candidate materials for microwave/millimeter-wave devices.
研究领域:
材料科学
·
电子工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Huanhuan Wang,Yanfeng Shang,Yuanxun Li,Yulong Liao,Limei Ruan,Yong Liu
The large negative temperature coefficient of resonant frequency ( τ f ) remains a critical bottleneck restricting the high-temperature application of ZnNb 2 O 6 microwave ceramics. In this work, a titanium-tungsten (TiW) complex cation co-doping strategy was employed to modulate the crystal structure and improve the intrinsic microwave properties of ZnNb 2 O 6 . The optimized ZnNb 1.98 (TiW) 0.02 O 6 ceramic exhibited excellent microwave performance, with a dielectric constant ( ε r ) of 24.0, a high Q×f value of 120,000 GHz, and a τ f of −100.0 ppm/°C at a sintering temperature of 1100 °C. To further address the thermal instability issues, a composite ceramic system combining (1-x) ZnNb 1.98 (TiW) 0.02 O 6 with xNi 0.5 Ti 0.5 NbO 4 was developed, which effectively compensated for the large negative τ f and strikes a balance between thermal stability and dielectric performance. When x = 0.6, the composite ceramic exhibited a higher ε r of 31.7, a Q×f value of 29,800 GHz, and τ f of 0 ppm/°C. These results demonstrate that the composite strategy enables simultaneous optimization of temperature stability and dielectric properties. This approach offers a promising route for thermally resistant microwave ceramics in extreme-environment applications.
研究领域:
材料科学
·
无机非金属材料
·
功能陶瓷
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介电材料
·
电子材料
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产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Lei Xiao,Lianwen Deng,Yingxiang Li,Zhenjun Qing,Yecheng Xi,Jiahui Zhu,Sen Peng
TiSnNbTaGa 2 O 12 (TSNTGO) high–entropy dielectric ceramic was successful synthesized using the solid-state reaction method. X–ray diffraction (XRD), Rietveld refinement and transmission electron microscopy (TEM) were used to verify that all samples have rutile structure of P42–mnm space group. The analysis of Raman spectra proved that the ε r exhibited a contrary changing trend as that of Raman shift near 822 cm −1 , and the same similar relationship occurred between Q×f values and full width at half maximum (FWHM). The exploration of complex chemical bonding theory (P–V–L theory) for TSNTGO ceramics suggested that the bond ionicity played a dominant role in ε r , while Q×f and τ f were primarily determined by lattice energy and bond energy, respectively. Notably, the TSNTGO ceramics sintered at 1275 ℃ demonstrated optimal microwave dielectric properties of ε r = 33.62 ± 0.03, Q×f = 51,832 ± 1000 GHz ( f 0 = 6.4 GHz), and τ f = –0.38 ± 0.16 ppm/℃.
研究领域:
材料科学
·
固态物理
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·Vol. 47
·期 1
·118759
·
IF 6.3
Mingfei Cheng,Yiyang Cai,Changzhi Yin,Xiaoqiang Song,Jiaqing Yang,Weicheng Lei,Zihang Chen,Yaqing Hu,Yaodong Liu,Xiaoxiao Li,Wenzhong Lu,Wen Lei
The poor sinterability and intrinsically positive τ f of BaZr(PO 4 ) 2 ceramics were addressed by introducing ZnO as a sintering aid and property modifier. In a conventional solid-state reaction route, ZnO promoted liquid-phase sintering through the in situ formation of BaZn 2 (PO 4 ) 2 , enabling near-full densification (>99% relative density) at 1250 °C. The ZnO content strongly affected phase evolution, microstructure, and microwave dielectric properties. The Q × f value reached a maximum at ∼4 wt% ZnO and then decreased because of losses associated with the secondary phase and increased grain-boundary density. Notably, τ f could be systematically tuned from positive to negative values through compensation by the negative- τ f BaZn 2 (PO 4 ) 2 phase. The optimized composition (4 wt% ZnO) exhibited ε r ≈ 10.1, Q × f ≈ 36,300 GHz, and τ f ≈ +0.4 ppm/°C. These results identify a promising microwave dielectric material that can be densified at a lower temperature and establish a practical strategy for tailoring τ f in phosphate ceramics through controlled secondary-phase formation.
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高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Huaicheng Xiang,Yuheng Zhang,Junqi Chen,Yang Zhou,Ying Tang,Jinwu Chen,Liang Fang
Bi 1– x Ho x VO 4 (0.1 ≤ x ≤ 0.9) ceramics were prepared via a solid-state reaction method, and all the ceramics could be well densified in the 920–980 °C range. The ceramics with 0.1 ≤ x < 0.4 were composed of both monoclinic scheelite (M) and tetragonal zircon (T) phases, and a single M phase could be obtained in the range of x ≥ 0.4. The measured ε r decreased from 58.9 ( x = 0.1) to 14.7 ( x = 0.9), so do the calculated values ( ε r(C − M) = 34.3–12.1), and the main reason for ε r > ε r(C − M) was the rattling of Ho 3+ in the dodecahedron. Two points with zero τ f appeared in Bi 1 – x Ho x VO 4 (0 ≤ x ≤ 1) ceramics, and the best microwave dielectric properties with ε r = 16.6, Q × f = 18,400 GHz ( f = 10.69 GHz), and τ f = +3.29 ppm/°C were obtained in the Bi 0.2 Ho 0.8 VO 4 ceramic. The change in temperature coefficient of ionic polarizability ( τ αm ) caused by the rattling effect of cations is the physical essence that affects τ f . Therefore, the rattling effect can be used as an effective mechanism to regulate τ f in low- ε r materials. Furthermore, there was no chemical reaction between Bi 1 – x Ho x VO 4 and Ag electrode, which indicates potential applications in low-temperature co-fired ceramic (LTCC) technology.
研究领域:
材料科学
·
电子材料
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2026
·
IF 16.8
Jing Ye Jin,Mo Wei,Yu Hui Huang,Qing Wei Zhou,Kai Xin Song,Bing Liu
Achieving a near-zero temperature coefficient of resonant frequency ( τ f ) while maintaining high quality factor ( Q ), typically reported as Q × f ( Qf ), in microwave dielectric ceramics is a significant challenge. In this work, a core-shell structural engineering strategy is proposed for efficient τ f regulation in MgF 2 –0.5 wt% LiF (MFL0.5) ceramics, which exhibit excellent microwave dielectric performance ( ε r = 5.09, Qf = 100,733 GHz) but suffer from a large negative τ f (−67.4 ppm/°C). Instead of dispersing temperature-compensation phases throughout the matrix, a pre-densified TiO 2 ceramic with positive τ f is introduced as a compact core embedded within the MFL0.5 shell, forming an integrated core-shell architecture. Experimental results show that a near-zero τ f of −1.97 ppm/°C can be achieved with only ∼1.27 wt% TiO 2 , while retaining a high Qf value of 50,302 GHz. In contrast, conventional MFL0.5–TiO 2 composite ceramics require 20 wt% TiO 2 to achieve similar τ f compensation, resulting in a significant decrease in Qf to 25,933 GHz. Electric-field distribution simulations highlight the enhanced electric filling factor of the TiO 2 core, which plays a key role in efficient τ f regulation. This core-shell architecture provides a highly effective strategy for regulating τ f with minimal dielectric loss penalty, offering a promising pathway for the development of high-performance, low- ε r microwave dielectric ceramics for advanced communication systems.
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高影响因子
危险品化学品经营许可证（带存储）