JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 23
·21693-21701
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IF 2.22
Zhou Fuming,Wang Hao,Guo Jianming,Yang Hui,Li LingFeng,Zhang Qilong
Microwave dielectric ceramics Sr 2 CeO 4 + n wt% Li 2 CO 3 —Bi 2 O 3 (LB) (1 ≤ n ≤ 4, L: B = x : y , weight ratio) were prepared by a traditional solid-state reaction method. The effects of LB additives on the phase formation, microstructure, sintering behavior, and microwave dielectric properties of Sr 2 CeO 4 ceramics were investigated. The sintering temperature can be reduced obviously from 1270 to 950 °C because of the liquid phase formation of LB. Single-phase Sr 2 CeO 4 ceramics with dense structure and homogenous grains were obtained by adding 1wt% LB. With LB content increasing, Q × f values would decrease because secondary-phase SrCeO 3 appeared in the ceramics. When the content of LB was fixed at 1 wt%, the sintering temperature and Q × f value would decrease simultaneously with the ratio of Li 2 CO 3 increasing. Desirable performances of Sr 2 CeO 4 + 1wt% LB ceramics: ( ε r = 14.36, Q × f = 102,023 GHz and τ f = − 66.42 ppm/°C, L:B = 2:8) and ( ε r = 13.56, Q × f = 70,109 GHz, τ f = − 64.17 ppm/°C, L:B = 8:2) can be achieved at 1075 °C and 950 °C, respectively, suggesting that Sr 2 CeO 4 –LB ceramics have a great potential for millimeter-wave applications.
研究领域:
材料科学
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陶瓷
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微波工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wenzhuo Chen,Jungu Xu,Chenjie Lou,Mingxue Tang,Xia Deng,Jiasheng Lv,Jing Fang,Jibran Khaliq,Laijun Liu,Qi Zhang
Sr 2 CeO 4 possesses structural characteristic of one-dimensional (1D) edge-sharing CeO 6 octahedral chains, exhibits superior phase and chemical stability compared to the perovskite SrCeO 3 . There have been previous attempts to improve electrical conductivity through proton conduction by acceptor-doping of Yb on the Ce site. However, its electrical conductivity remained low, for instance, at 500 °C, the reported value was 3.16 × 10 −7 S/cm, hence limiting its practical applications. In this paper, we synthesized four new rare earth doped Sr 2 Ce 0.95 M 0.05 O 3.975 (where M = Y, Dy, Er, Tb) by the solid state reaction method. We thoroughly investigated their phases, electrical properties, and stability. Additionally, for the first time, we investigated the proton and oxide ion conduction mechanisms in Sr 2 CeO 4 -based materials using a bond-valence-based method. This analysis revealed a clear 1D conduction along the c -axis within the CeO 6 tetrahedral chains and 2D conduction within the a-c plane, respectively. The findings revealed that all doped materials showed obvious proton conduction, alongside partial oxide ion conduction. Notably, the Er-, Dy-, and Y-doped samples demonstrated significantly improved conductivity under wet condition (with a water partial pressure of ∼0.03 atm) at 500 °C, reaching approximately ∼ 10 −4 S/cm. This is nearly three orders of magnitude higher than the previously reported Yb-doped Sr 2 CeO 4 .
研究领域:
材料科学
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固体物理
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2023
·Vol. 13
·期 6
·955
·
IF 2.7
Qi Su,Jingjing Qu,Fei Liu,Changlai Yuan,Xiao Liu,Mingwei Su,Liufang Meng,Guohua Chen
Ti4+-ion-doped (n+ 1)SrO −nCeO2(n= 2) ceramic systems were prepared with the conventional solid-state reaction method, and the effects of the phase structures and compositions, sintering behaviors, microstructures and microwave dielectric properties of these ceramic systems were investigated in detail as a function of TiO2content. The analytical results of the XRD patterns show that the pure (n+ 1)SrO −nCeO2(n= 2) system is a composite-phase ceramic system with coexisting SrCeO3and Sr2CeO4phases (represented as a SrCeO3+ Sr2CeO4system), which belong to the orthogonal structures of the Pmcn (62) and Pbam (55) space groups, respectively. For thexTiO2-(1 − x) (SrCeO3+ Sr2CeO4) (x= 0.1–0.4) ceramic samples, the secondary phase Sr2TiO4can also be detected within the range of the investigated components. Meanwhile, the Raman spectroscopy, SEM-EDS, and HRTEM (SAED) analysis results also verified the correctness and consistency of the phase structures and compositions for all the given specimens. In addition, complex impedance spectroscopy was used to detect the conductive behavior of these compound ceramic systems, and the calculation results show that the appropriate addition of Ti4+-ions can make the SrCeO3+ Sr2CeO4system have better thermal stability. The composition ofx= 0.2 multiphase structural ceramic sample sintered at 1330 °C for 4 h has a near zero τfvalue of ~−4.6 ppm/°C, a moderateεrof ~40.3 and a higherQ×f~44,020 GHz (at 6.56 GHz). The relatively superior-performing ceramics developed in this work are expected to provide a promising microwave dielectric material for communication components.Keywords:phase structures and compositions;SrCeO3+ Sr2CeO4system;TiO2addition;microwave dielectric properties
研究领域:
材料科学
·
陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 22
·4006
·
IF 4.329
Qinlong Wang,Hao Wang,Caixia Zhang,Qilong Zhang,Hui Yang
High-frequency communication equipment urgently needs substrate materials with lower dielectric loss, better heat dissipation, and higher stability, to ensure real-time low-loss and high-speed signal transmission. The core-shell structure of Sr2CeO4@SiO2was prepared by the sol-gel method, and the modified powders with different volume contents were introduced into the cyclic olefin copolymer (COC) to prepare hydrocarbon resin-based composites. Due to the protective effect of the SiO2shell, the stability of the powders is significantly improved, and the moisture barrier and corrosion resistance of the composites are enhanced, which is conducive to the normal operation of electronic equipment in harsh and complex environments. When the filler content is 20vol%, the composite has a dielectric loss of 0.0023 at 10 GHz, a dielectric constant of 3.5, a thermal conductivity of 0.9 W·m−1·K−1, a water absorption of 0.32% and a coefficient of thermal expansion of 37.7 ppm/°C. The COC/Sr2CeO4@SiO2composites exhibit excellent dielectric properties and thermal conductivity, while maintaining good moisture resistance and dimensional stability, which shows potential application prospects in the field of high-frequency substrates.Keywords:polymer composite;dielectric loss;thermal conductivity;stability
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
Journal of Materiomics
·
2025
·
IF 9.6
Tauqeer Ahmad,Wen Lei,Burhan Ullah,Wen-zhong Lu
A series of (Sr 0.4 Ce 0.4 )TiO 3 + 4% (in mass) Sr 2 CeO 4 + x % B 2 O 3 (SCTO + 4% SCO + x % B 2 O 3 for 1≤ x ≤ 5) composites were synthesized via solid-state reaction to investigate the effects of Sr 2 CeO 4 and B 2 O 3 additives on their structural evolution and microwave dielectric properties. X-ray diffraction (XRD) and Rietveld refinement confirmed the dominant orthorhombic phase (O-phase), with SCO as a secondary phase, indicating a chemically stable composite system. HRTEM and SAED analyses further confirmed the formation of the O-phase through direct observation of the superlattice reflections. Microstructural evolution demonstrated B 2 O 3 -assisted liquid-phase sintering, reducing porosity (0.017→ 0.006) and increasing grain size (3.34 → 6.01 μm) with increasing x % (in mass). Raman spectroscopy verified octahedral tilting and Ce–O stretching, while B 2 O 3 incorporation modified the TiO 6 network via BO 3 /BO 4 interactions. The ε r decreased from 113 (SCTO) to 27 at x = 5%, while τ f improved from +213 to +12×10 –6 /°C. The reduction in ε r arises from a complex interplay of internal factors (ionic polarizability) and external factors (porosity, and density), whereas the variation in τ f is governed by compensating effects from Sr 2 CeO 4 and B 2 O 3 . Optimal microwave performance was achieved at x = 5%, with Q×f = 43,603 GHz, ε r =27, and τ f of +12×10 –6 /°C. The study demonstrates that SCO and B 2 O 3 act as effective modifiers, enhancing densification and dielectric properties in SCTO-based microwave ceramics.
研究领域:
材料科学
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电子材料
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功能陶瓷
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介电材料
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微波技术
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固态化学
✓ 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）