JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Chun Tong,Xinlei Shen,Chang Feng,Xia Feng,Haikui Zhu,Lixi Wang
Temperature-stable ULTCC composite (1- x )Li 3 AlMo 3 O 12 - x Li 0.5 Bi 0.5 MoO 4 ceramics were prepared by solid-state reaction method. X-ray and EDS results showed that Li 3 AlMo 3 O 12 phase and Li 0.5 Bi 0.5 MoO 4 phase exist independently, and no other phase is generated. Due to the low sintering temperature of both two phases, the composite ceramics can obtain high density at 560 ℃. Microwave dielectric properties mainly depend on the ceramic Li 0.5 Bi 0.5 MoO 4 content x , the addition of Li 0.5 Bi 0.5 MoO 4 effectively increases the τ f of Li 3 AlMo 3 O 12 from −65.05 ppm/℃ to 4.96 ppm/℃, but caused the dielectric loss increase. When x =0.45 and sintered at 560 ℃, microwave dielectric properties of 0.55Li 3 AlMo 3 O 12 -0.45Li 0.5 Bi 0.5 MoO 4 ceramics with close zero τ f : ε r = 15.32, Q × f = 13,158 GHz, τ f = 4.96 ppm/℃.
研究领域:
材料科学
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电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2023
·Vol. 52
·期 11
·7164-7170
·
IF 2.1
Li Yingxiang,Liang Deyin,Zhang Xing,Xiong Zhe,Tang Bin,Si Feng,Fang Zixuan,Li Hao,Shi Zitao,Chen Jingjing
This study presents the dielectric properties of Ba 2 Zr 2 Si 3 O 12 ceramics, synthesized using the solid state method. The cubic crystal structure of Ba 2 Zr 2 Si 3 O 12 ceramics was conclusively verified through the analysis of XRD patterns and subsequent structural refinement. Refined lattice parameters of a = b = c = 10.23178 Å were found, with a corresponding unit cell volume of V = 1071.159026 Å 3 . The grain microstructure of the ceramics was characterized using SEM, which showed density of 97.6% for the Ba 2 Zr 2 Si 3 O 12 ceramic. The Si-O bond valences ( V Si-O ) were found to be closely related to the τ f of the Ba 2 Zr 2 Si 3 O 12 ceramics. The microwave dielectric properties of the Ba 2 Zr 2 Si 3 O 12 ceramics sintered at 1490°C were ascertained to be ε r = 15.08, Q × f = 14885 GHz ( f = 9.9 GHz), and τ f = −78.6 ppm/°C.
研究领域:
材料科学
·
无机非金属材料
·
微波介质陶瓷
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 15
·11625-11631
·
IF 2.779
Xing Zhuo,Weng Juhai,Ma Chi
A series of Ga 3+ -doped Zn 2 GeO 4 willemite ceramics, in a general formula Zn 2+0.5 x Ge 1− x Ga x O 4 (0.1 ≤ x ≤ 0.4), were prepared and the influence of Ga 3+ doping on the phase composition, structure, microstructure, and microwave dielectric properties were studied. XRD, SEM, and Raman analysis evidence that by moderate gallium substitution in the nominal Zn 2 GeO 4 , the unfavorable ZnO phase was suppressed, while a low-loss ZnGa 2 O 4 phase was induced. With increasing doping content, the ZnGa 2 O 4 phase increases in phase percentage and becomes dominant (~ 69%) after x = 0.3. Due to the mixture rule, both relative permittivity and quality factor were improved, which is related to the superior dielectric properties of ZnGa 2 O 4 compared to Zn 2 GeO 4 . The microwave dielectric properties show a remarkable dependence on the composition. Sintered at 1230 °C, a combination of dielectric performances with ε r ~ 9.4, Q × f ~ 97,000 GHz, and τ f ~ − 30.7 ppm/°C was accessed in the x = 0.4 composition.
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 MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 23
·20247-20252
·
IF 2.324
Zhang Yun,Ding Shihua,Song Tianxiu,Huang Long,Zhang Xiaoyun
Rutile-structured CoTiNb 2 O 8 ceramics were synthesized via traditional solid-state route. The effects of LiF addition on their sintering behavior, phase composition, microstructure and microwave dielectric properties were investigated systematically in this study. The sintering temperature was successfully lowered to 950 °C by a small amount (1 wt%) of sintering aid. XRD and EDS results indicated that chemical reaction between LiF and host ceramic took place during sintering process. And CoTiNb 2 O 8 with Li 0.8 Co 0.2 Nb 0.96 O 3 second phase coexisted in the entire composition range. The addition of LiF to the CoTiNb 2 O 8 ceramics induced a limited degradation in microwave dielectric properties. The ε r and Q × f values of the low-fired CoTiNb 2 O 8 ceramics ranged from 39.4 to 53.9 and 17,580 GHz to 20,147 GHz, respectively. While the τ f decreased in negative values with increasing LiF content. When sintered at 950 °C, the CoTiNb 2 O 8 ceramic doped with 1 wt% LiF had excellent microwave dielectric properties: ε r = 53.9, Q × f = 20,147 GHz, and τ f = 77.2 ppm/°C, making them promising for LTCC applications.
研究领域:
材料科学
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电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Kang Du,Chang-Zhi Yin,Yan-Bo Guo,Chao Zhang,Xiao-Chuan Wang,Wen-Zhong Lu,Wen Lei
The CaSnSi 1- x Ge x O 5 (0 ≤ x ≤ 1.0) microwave dielectric ceramics were prepared using traditional solid reaction sintered at 1450 °C-1500 °C for 5 h, and the substitution of Ge 4+ for Si 4+ formed the CaSnSi 1- x Ge x O 5 solid solution at 0 ≤ x ≤ 1.0. The phase transition from monoclinic with A 2/ a space group to triclinic with A 1 ‾ space group at CaSnSi 1- x Ge x O 5 ceramics was clarified by Rietveld refinement and high-resolution transmission electron microscopy/selected area diffraction. The crystal structure, X-ray diffraction patterns , and microwave dielectric properties ( ε r = 11.28, Q × f = 72,900 GHz at 11.62 GHz, and τ f = −62.9 ppm/°C) of novel single-phase CaSnGeO 5 ceramic were initially reported. In single-phase area, the increase in SnO 6 octahedral distortion could reduce the τ f value of CaSnSi 1- x Ge x O 5 ceramics (0 ≤ x ≤ 0.6) to near zero. In multiphase area, the near-zero τ f value (τ f = +5.2 ppm/°C) was obtained at x = 0.7. The remarkable change between +5.2 ppm/°C ( x = 0.7) and −77.8 ppm/°C ( x = 0.8) of τ f value was attributed to the appearance of ε r anomaly peak (T 1 = 125 °C). The optimal microwave dielectric properties ( ε r = 11.70, Q × f = 37,900 GHz at 12.6 GHz, and τ f = +5.2 ppm/°C) of CaSnSi 1- x Ge x O 5 ceramics were obtained at x = 0.7.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Xiaowen Hu,Jinwu Chen,Jie Li,Huaicheng Xiang,Ying Tang,Liang Fang
Two zircon-structured ceramics AEuV 2 O 8 (A = Bi, La) were prepared with optimal sintering temperatures of 900 °C and 1375 °C, respectively. They exhibited sharp contrast performances with medium ε r ∼ 28.7 ± 0.1, Q × f ∼ 14,000 ± 300 GHz, and large positive τ f ∼ 75.7 ± 2.0 ppm/°C for BiEuV 2 O 8 , whereas low ε r ∼ 10.4 ± 0.1 Q × f ∼ 25,100 ± 300 GHz, and negative τ f ∼ − 40.7 ± 2.0 ppm/°C for LaEuV 2 O 8 . The rattling effect at the A-site was more dominant in determining microwave dielectric properties than that of compressed V 5+ at the B-site. It resulted in the higher ε r , lower Q × f and τ ε , and larger τ f of BiEuV 2 O 8 than those of LaEuV 2 O 8 . Besides, their Q × f was related with the relative density, bond valence and FWHM of the B 1 g Raman mode.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 90
·86889-86903
·
IF 3.289
H. L. Pan,Q. Q. Liu,Y. H. Zhang,H. T. Wu
Wolframite structure Zn1−xCoxZrNb2O8 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) ceramics were prepared by the conventional solid state method. The crystal structures were studied via X-ray diffraction, and lattice vibrational modes were obtained by Raman spectroscopy. It could be found that all the A-site (Zn2+/Co2+, Zr4+) and B-site (Nb5+) cations were octahedrally coordinated with oxygen anions from the diagrammatic sketch of the crystal structure. Rietveld refinement was used to analyze the crystal structure and the lattice parameters were obtained. Based on the complex chemical bond theory and lattice parameters, intrinsic factors such as the bond ionicity, lattice energy, bond energy and coefficient of thermal expansion were calculated. Based on the results, Nb–O bonds played an important role in affecting the microwave dielectric proprieties of Zn1−xCoxZrNb2O8 ceramics. Co2+ substitution would affect the crystal structure and influence the microwave dielectric properties. The tendency of the dielectric constant (εr) could be predicted by the polarizability and bond ionicity of Nb–O bonds, and the εr showed the same tendency with Raman shifts of Nb–O vibration modes. The variation of the quality factor (Qf) could be explained by the change of the lattice energy of Nb–O bonds and the full width at half maximum (FWHM) values of Nb-site Raman modes. The temperature coefficient of resonant frequency (τf) showed the same tendency with the bond energy, octahedral distortion and bond valence of Nb–O bonds, and the opposite tendency with the thermal expansion coefficient.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 13
·10183-10193
·
IF 2.779
Zhang Liangbin,Mei Hongrong,Rao Zhenggang,Shu Longlong,Li Chunchun
In this work, a strategy was demonstrated to reduce the sintering temperature of Mg 2 SiO 4 ceramics while keeping the macrostructure unchanged, through an appropriate amount of low melting point Ge substitution for B-site Si. A series of Mg 2 Si 1 − x Ge x O 4 ( x = 0.1–0.4) ceramics were prepared by a solid-state reaction method. Influences of Ge substitution on the sintering behavior, crystal structure, and microwave dielectric properties were studied. By comparison, the Ge-substituted samples could be effectively sintered at relatively lower sintering temperatures (~ 1370 °C), which is more than 100 °C lower than the nominal Mg 2 SiO 4 . In addition, the optimum microwave dielectric performance was achieved in the sample with x = 0.4, with the relative density ~ 97%, the relative dielectric constant ( ε r ) of 7.2, the quality factor ( Q × f ) of 75,794 GHz, and the temperature coefficient of the resonance frequency ( τ f ) of − 41.2 ppm/°C. This compositional regulation provides a paradigm for improving the sintering characteristics of silicate.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Xianqiang Chen,Binfeng Zhao,Naichao Chen,Jin Cheng,Mingzhao Dang,Feng Wang,Xinwei Xu,Hong Wang
Low-temperature-fired microwave ceramics are key to realizing the integration and miniaturization of microwave devices. In this study, a facile wet chemical method was applied to synthesize homogenous nano-sized CaF 2 powders for simultaneously achieving low-temperature sintering and superior microwave dielectric properties . Pure CaF 2 ceramics sintered at 950 °C for 6 h with good microwave dielectric properties (ε r = 6.22, Q×f = 36,655 GHz, and τ f = −102 ppm/°C) was achieved. The microwave dielectric properties of the CaF 2 ceramics were further improved by introducing LiF as a sintering aid. The sintering temperature of CaF 2 -based ceramics was effectively lowered from 950 °C to 750 °C with 10 wt% LiF doping, and excellent microwave dielectric properties (ε r = 6.37, Q×f = 65,455 GHz, and τ f = −71 ppm/°C) were obtained.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Y.J. Niu,M.T. Liu,M.F. Li,J.X. Bi,H.T. Wu
Wolframite-structured Zn 1-x Mg x ZrNb 2 O 8 (0 ≤ x ≤ 0.1) ceramics were synthesized by the conventional solid-state method. The effects of Mg 2+ substitution on the sinter ability, crystal structures and microwave dielectric properties were systematically investigated. The Q·f values increased from 46,800 GHz to 53,400 GHz when the x value increased from 0 to 0.1. Based on the complex chemical bond theory, the intrinsic parameters were calculated to analyze the mechanism of dielectric loss in Zn 0.9 Mg 0.1 ZrNb 2 O 8 . The total lattice energy and bond energy of the Zn 0.9 Mg 0.1 ZrNb 2 O 8 were higher than that of ZnZrNb 2 O 8 , which was corresponding with the decrease of dielectric loss in the wolframite-structured compounds. The dielectric constant ( ε r ) and temperature coefficient of resonant frequency ( τ f ) of Zn 1-x Mg x ZrNb 2 O 8 ceramics were also heavily influenced by the addition of Mg 2+ . Typically, the dense Zn 0.9 Mg 0.1 ZrNb 2 O 8 ceramics sintered at 1200 °C exhibited excellent microwave dielectric properties with ε r = 27.82, Q·f = 53,400 GHz and τ f = −45.82 ppm/°C.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2013
·
IF 1.789
Qing Ma,Songping Wu,Yingxian Fan
Zn 2 SnO 4 ceramics were synthesized by the solid-state method. B 2 O 3 was added into the system to lower the sintering temperature . B 2 O 3 -doped Zn 2 SnO 4 materials were characterized by X-ray diffraction (XRD), electron microscopies (SEM/TEM/HRTEM/EDS), Raman and XPS spectroscopies. The inverse-spinel Zn 2 SnO 4 ceramics (containing 1 wt% B 2 O 3 ) sintered at 975 °C exhibited good microwave dielectric properties : ε r =9.3, Q × f =62,000 GHz and τ f =−50 ppm/°C. Zn 2 SnO 4 ceramics with low sintering temperatures are promising candidate materials for low-temperature cofired 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
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Liang Shi,Xueying Wang,Rui Peng,Yongcheng Lu,Cheng Liu,Dainan Zhang,Huaiwu Zhang
A series of Mn 2+ -doped Mg 1-x Mn x Ta 2 O 6 (x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ceramics were synthesized by solid-state reaction method. The influence of introducing Mn–O bonds as a partial replacement for Mg–O bonds on the lattice and microwave dielectric properties was systematically investigated. XRD and Rietveld refinement confirm that Mn 2+ occupies the 2a Wyckoff position and forms a pure trirutile phase. Moreover, based on the chemical bond theory, the dielectric constant is mainly affected by the ionicity of the Ta–O bond. The lattice and dielectric properties remain relatively stable with Mn 2+ doping below 0.1, but excessive Mn 2+ doping leads to pronounced distortion of the lattice, which is not beneficial for lattice stability and microwave dielectric properties. Introducing an appropriate amount of Mn–O bonds with high bond dissociation energy facilitates MgO6 octahedron stability, which improves the thermal stability of the lattice. Accordingly, the microwave dielectric properties for 0.06 Mn 2+ -doped MgTa 2 O 6 ceramics were determined: ε r = 28, Q × f = 105,000 GHz (at 7.5 GHz), τ f = 19.5 ppm/ ° C.
研究领域:
材料科学
·
无机化学
✓ 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）