ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Shuai Ma,Xiaohua Zhang,Jie Zhang,Xiaohui Zhang,Yu Liu,Chenglong Yu,Zhenxing Yue
Low-loss microwave dielectrics are of significant importance for the miniaturization and integration of microwave devices. In this paper, the ceramics of nominal composition Mgn+1TinO3n+1 (n = 3–6) are synthesized, and the correlations among their phase compositions, defect behaviors, and microwave dielectric properties are systematically investigated. The analyses indicate that the Mgn+1TinO3n+1 ceramics are a biphasic system consisting of hexagonal ilmenite-structured MgTiO3 and cubic spinel-structured Mg2TiO4. The Rietveld refinement results demonstrate that as the n value increases, the content of the MgTiO3 phase gradually increases, while that of the Mg2TiO4 phase decreases. The results of the thermally stimulated depolarization current (TSDC) indicate that the oxygen vacancy-related defects are considered to be the main types of defects in Mgn+1TinO3n+1. As the value of n increases, the increase of the MgTiO3 phases with a more stable crystal structure leads to a gradual decrease in the concentration of oxygen vacancies. The Mgn+1TinO3n+1 ceramics exhibit excellent microwave dielectric properties at n = 6: εr = 17.55, Q × f = 284,600 GHz, and τf = −46.39 ppm/°C. In addition, the relationship between the dielectric constant and the electric field distribution is solved utilizing high-frequency structure simulator (HFSS) software, and the Q × f values are also predicted. The low-frequency dielectric temperature spectra and direct current pulse charge/discharge tests show that the low-loss Mgn+1TinO3n+1 ceramics can be good candidates for microwave capacitors even when operated under high-temperature conditions.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wengao Pan,Qingping Lin,Lili Xiao,Shihao Feng,Ying Li,Jie Gao,Pengfei Yue,Guoshang Zhang
Perovskite structural LiBaF 3 ceramics with excellent microwave dielectric properties were synthesized using traditional solid-state method. By regulating the sintering temperatures from 600 °C to 675 °C, LiBaF 3 ceramics exhibit tunable dielectric constant ( ε r ) from 12.42 to 13.72, adjustable Q × f value from 55000 GHz to 73000 GHz, and regulable temperature coefficient of resonance frequency ( τ f ) from −36.78 ppm/°C to −34.68 ppm/°C. The properties are strongly associated with the density, and can be further optimized by 0.5 wt%TiO 2 addition ( ε r = 14.43, Q × f = 56000 GHz, τ f = -1.26 ppm/°C). The LiBaF 3 ceramics also exhibit excellent compatibility with Ag and Al electrodes. Furthermore, relationships between multiscale structures and microwave dielectric properties of the ceramics were revealed. Oxidation behaviors between LiBaF 3 and O 2 would result in the lattice shrinkage, the introduction of defect level, the decrease of bandgap and density, and then deteriorating the microwave dielectric properties. All the findings make the LiBaF 3 ceramic a promising candidate for ULTCC application, and may facilitate the development of other novel microwave dielectric materials.
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
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yajie Wang,Ziyi Zhang,Jie Li,Ying Tang,Liang Fang
Excellent spinel microwave dielectric ceramics (1- x )Zn 2 TiO 4 - x Li 2 MgTi 3 O 8 (ZTLMT x , x = 1/3 and 2/3) were prepared at relatively low densification temperatures of 1100 °C and 1080 °C, respectively. A disordered cubic phase with space group Fd -3 m was formed at x = 1/3, whereas an ordered cubic phase with space group P 4 3 32 was formed at x = 2/3. The ceramics at x = 1/3 and 2/3 exhibited promising microwave dielectric properties of ɛ r = 18.27 and 22.96, Q × f = 91,877 GHz and 75,186 GHz, and τ f = −42.3 ppm/°C and −21.05 ppm/°C, respectively. The large deviation between the experimental ԑ r and theoretical ε th of 1/3 and 2/3 ceramics were 18.3 % and 57 %, respectively, due to the underestimation of the ionic polarizability of Ti 4+ . The difference in their ɛ r , Q × f , and τ f were discussed by the structure, FWHM of A 1g , lattice energy and bond energy in detail.
研究领域:
材料科学
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陶瓷学
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物理学
✓ 已验证
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
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 22
·8053
·
IF 3.748
Sen Peng,Chen Li,Chao Tang,Sheng Liu,Shengxiang Huang,Leilei Qiu,Lianwen Deng
In this work, novel MgCu2Nb2O8(MCN) ceramics were synthesized by the two-step sintering (TSS) technique, and the phase composition, crystal structures, and microwave dielectric properties were comprehensively studied. X-ray diffraction (XRD) and Raman analysis demonstrated that MCN ceramics are multi-phase ceramics consisting of MgNb2O6and CuO phases. X-ray photoelectron spectroscopy (XPS) was utilized to investigate the chemical composition and element valence of MgCu2Nb2O8ceramics. Scanning electron microscopy (SEM) analysis demonstrated dense microstructures in the MCN ceramics prepared at a sintering temperature of 925 °C. The microwave dielectric properties were largely affected by the lattice vibrational modes and densification level of the ceramics. The outstanding microwave dielectric properties of εr= 17.15,Q×f= 34,355 GHz, and τf= −22.5 ppm/°C were obtained for the MCN ceramics sintered at 925 °C, which are results that hold promise for low temperature co-fired ceramic (LTCC) applications.Keywords:MgCu2Nb2O8ceramics;crystal structure;annealing;microwave dielectric property
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 2
·1-10
·
IF 2.8
Guan Yeqing,Zhang Jinxian,Wang Fenglin,Li Wei,Mao Haijun,Liu Zhuofeng,Zhang Weijun,Chen Xingyu
The Ca 0.245 Li 0.325 Nd 0.395 Ti 1− x Sn x O 3 ( x = 0–0.12) ceramics were prepared by the traditional solid-state reaction method. The effects of Sn 4+ substitution for Ti 4+ on the phase composition, microstructure, and microwave dielectric properties of Ca 0.245 Li 0.325 Nd 0.395 Ti 1− x Sn x O 3 (CLNTS x ) were investigated in this work. The X-ray diffraction results showed that the ceramics had a single orthorhombic perovskite structure when x = 0–0.09. However, a secondary phase SnO 2 was observed with x > 0.09. The SEM micrographs indicated that the proper Sn 4+ substitution for Ti 4+ promoted the grain growth and homogenization. The analysis results of Raman spectroscopy revealed the correlation between vibration modes and microwave dielectric properties of CLNTS x ceramics with different Sn 4+ contents. The degree of cation order was related to the full width at half maximum (FWHM) of the Raman spectrum, and a lower FWHM value indicates higher cationic order and Q × f 0 value. The excellent microwave dielectric properties with ε r = 98, Q × f 0 = 3320 GHz, and τ f = 2.6 ppm/°C were obtained in the ceramics with x = 0.09 sintered at 1350 °C for 4 h.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Xinyuan Lyu,Luchao Ren,Le Xin,Zhengxin Li,Xianxin Zhang,Zheng Luo,Pengchao Shao,Yuxiao Zhang,Panpan Lyu,Mingwei Zhang
Fabrication of low-temperature co-fired ceramic (LTCC) densified at a low sintering temperature (<900 °C) is energy saving and environmentally friendly. Here, an interesting attempt has been made to lower the sintering temperature of MgGa2O4 by adding CuMoO4 for LTCC application. The sintering temperature of MgGa2O4 was remarkably reduced from 1410 to 900 °C, which contributed to energy saving. Furthermore, a series of studies on microstructure, sintering behavior, lattice parameters, and microwave dielectric characteristic of the samples were carried out. The occurrence of ion substitution between MgGa2O4 and CuMoO4, which affected the sintering densification, ionic polarizability, and Mg–O bond length, made the composites present various sintering and dielectric properties. Moreover, the full width half maximum (FWHM) value of the T2g peak in Raman spectra and lattice distortion were also analyzed to reveal the intrinsic interaction between structure and dielectric properties. Finally, the 0.5MgGa2O4–0.5CuMoO4 ceramics sintered at 900 °C showed the best comprehensive performance, εr = 6.8, Q × f = 15,800 GHz, τf = −54.2 ppm/°C. These promising properties make the composite more suitable for practical application.
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
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xinyang Wen,Huaicheng Xiang,Xin Mo,Qingfeng Li,Ying Tang,Liang Fang
To explore the effect of B-site ion variation in the garnet structure on the microwave dielectric properties, we introduced part of Y 3+ into Y 3 Ga 5 O 12 to form a series of Y 3 (Y x Ga 2- x )Ga 3 O 12 ( x = 0–0.9) ceramics. Rietveld refinements, based on the XRD data, reveal that the Y 3+ x Ga 5- x O 12 ( x = 0–0.8) ceramics crystallized in the garnet structure with the Ia -3 d space group, and two phases simultaneously coexisted in the x = 0.9 ceramics. The average B-site cations were compressed, A-site cations exhibited rattling, and the overall structure of Y 3+ x Ga 5- x O 12 ( x = 0–0.8) slightly expanded. As the concentration of Y 3+ at the B-site increased in pure-phase ceramics, the ε r (12.15–12.79) and τ f (−69.95 ∼ −60.72 ppm/°C) exhibited an upward trend, while the Q × f descended (101,902–79,209 GHz). The factors influencing the microwave dielectric properties were further examined by considering the ionic polarizability, bond valence, lattice energy, and packing fraction.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
C.H. Yang,H.L. Pan,Y.K. Yang,H.T. Wu
A series of Zn-doped Li 2 (Mg 1-x Zn x ) 3 TiO 6 (x = 0, 0.05, 0.10, 0.15, 0.2) ceramics were formed via the conventional solid-state process. Influence of Zn 2+ on the crystal structures, phase compositions, sintering characteristics and properties of Li 2 (Mg 1-x Zn x ) 3 TiO 6 (0 ≤ x ≤ 0.2) ceramics were systematically studied. XRD results showed that a single phase with the cubic rock-salt structure was formed for Li 2 (Mg 1-x Zn x ) 3 TiO 6 (0 ≤ x ≤ 0.15) and the second phase of Zn 2 TiO 4 could be detected with a further increase of the Zn 2+ contents. Some intrinsic parameters were calculated in order to investigate the correlations between these parameters of Mg/Zn O bonds and microwave dielectric properties . As the Zn 2+ content increases, optimum ε r values exhibited an increasing trend, which could be explained by the variations of the polarizability and bond ionicity of Mg/Zn O bonds. The decrease of maximum Q·f values for Li 2 (Mg 1-x Zn x ) 3 TiO 6 (x = 0, 0.05, 0.10, 0.15, 0.2) ceramics could be predicted by the decrease of the packing fraction and lattice energy of Mg/Zn O bonds. τ ƒ values showed close relationship with the bond energy and thermal expansion coefficient of Mg/Zn O bonds. Excellent combined microwave dielectric properties with ε r = 15.46 (at 10.9 GHz), Q·f = 125,453 GHz (at 8.6 GHz) and τ f = −32.35 ppm/°C were obtained for Li 2 (Mg 0.85 Zn 0.15 ) 3 TiO 6 ceramic sintered at 1600 °C.
研究领域:
材料科学
·
电子材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Xiaorong Zhang,Xiaochuan Wang,Ping Fu,Wenzhong Lu
YAG ceramics with good dielectric properties were prepared via a modified pyrolysis method, with yttrium nitrate as the yttrium source and combined aluminium sulphate and aluminium nitrate as aluminium sources, and subsequent sintering in a muffle furnace. The effects of the different aluminium sources on the powder characteristic and the impact of sintering temperature , sintering aids (TEOS) and additive (TiO 2 ) on the dielectric properties of the ceramics were studied. The results show that well-dispersed pure YAG nano-powders can be obtained after calcination at 1000 °C with an aluminium sulphate and aluminium nitrate molar ratio of 1.5:2. The relative density, permittivity ( ε r ) and quality factor ( Q × f ) of the YAG ceramics increase with sintering temperature and TEOS addition. TiO 2 can greatly promote τ f to near-zero but decreases Q × f . The relative density, ε r , Q × f and τ f of the YAG–1 wt% TEOS–1 wt% TiO 2 ceramic obtained at 1520 °C are 97.6%, 9.9, 71, 738 GHz and −30 ppm/°C, respectively.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yang Yang,Weishuang Fang,Ning Zhang,Huaicheng Xiang,Ying Tang,Jie Li,Liang Fang
CaEu C O 4 ( C Ga, Al) microwave dielectric ceramics were produced through a solid-state reaction. Orthorhombic olivine CaEuGaO 4 ( pnma ) exhibits a lower permittivity ( ε r = 9.7), a higher quality factor ( Q × f = 82,049 GHz), and a larger negative resonant frequency temperature coefficient ( τ f = −54.6 ppm/°C). CaEuAlO 4 , which has a similar chemical formula, exhibits a perovskite-like structure ( I 4/ mmm , K 2 NiF 4 -type), and its microwave dielectric properties are ε r = 18.9, Q × f = 43,132 GHz, and τ f = −1.6 ppm/°C. The difference in their structures is mainly caused by the properties of the Ga (III) atom. The difference in their dielectric properties can be proved to be affected by the “rattling” effect of Eu 3+ through the bond valence theory. The relationship between the covalence ( f c ) and the bond strength ( S ) was investigated, and the higher bond strength might be the main reason for the higher Q × f in CaEuGaO 4 ceramic.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Bing Liu,Ke Sha,Meng Fei Zhou,Kai Xin Song,Cheng Chao Hu,Cheng Lu
A cold sintering process is adopted to pre-densify CaF 2 ceramics from 85.7% at 300 MPa to 91.7% at 750 MPa. Subsequent post-annealings at 1000–1150 °C lead to further improvements in densification, where great enhancements of grain size and crystallinity are also observed from the scanning and transmission electron micrographs. Significant advances in Qf values are achieved in the post-annealed CaF 2 ceramics. The optimum Qf value (80,522 GHz) is achieved after cold sintering at 750 MPa and post-annealing at 1000 °C, which is three times higher than the conventional sintered one at 1000 °C (26,448 GHz). Moreover, the obtained low- ε r (5.9–6.5) of CaF 2 ceramics suggests broad application prospects in the high-band microwave communications. A microstrip patch antenna is fabricated using the CaF 2 ceramics as the substrate, which operates at 7.89 GHz in the C-band, with an S 11 of −13.4 dB, simulated high gain and efficiency of 6.41 dBi and −0.56 dB, respectively.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）