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
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
✓ 已验证
产品关联
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
·
电子材料
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Materials
·
2020
·
IF 2.705
Tian Huanrong,Liu Xin,Yang Yaokang,Wu Haitao,Zhang Zhiliang
Ce2(Zr0.94Sn0.06)3(MoO4)9 (CZSM) ceramics were synthesized via a traditional solid-state method. The effects of Sn-substitution on phase composition, microstructure, and microwave dielectric properties as a function of sintering temperature were discussed. The XRD results indicated that all the samples exhibited a single phase. The chemical bonds of CZSM ceramics were calculated based on P-V-L theory, which could be used to evaluate the relationship between structure and microwave dielectric properties. The tendency of dielectric constant was depended on the theoretical dielectric polarizability and bond ionicity. Moreover, the improvement of Q·f value was ascribed to the increase of packing fraction. The reduced τf value could be explained by decrease of the bond energy, enhanced the co-efficient of thermal expansion and increase of bond valence (VZr(Sn)). The complex permittivity values were obtained from infrared reflectivity spectra. The dielectric permittivity and loss were 10.92 and 3.08 × 10−4, respectively, which agreed well with the measured value. Typically, the optimal microwave dielectric properties of εr = 10.35, Q·f = 59,660 GHz (at 9.70 GHz), and τf = −7.52 ppm/°C were achieved in CZSM ceramics sintered at 800°C for 6 h.
研究领域:
材料科学
·
陶瓷工程
·
固体化学
·
电磁材料
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Mingjia Lu,Xin Ouyan,Songping Wu,Rongyun Ge,Rui Xu
Self-assembled porous ZnGa 2 O 4 particles were synthesized through a facile hydrothermal route in this work. The phase evolution and microstructure of specimens were identified by XRD and SEM. Various morphologies (i.e. porous, nanorods or spherical particles) and size (nano or micro-sized) could be rationally designed through altering the reaction conditions. Hydrothermal ZnGa 2 O 4 particles exhibited an outstanding microwave dielectric performance, i.e. a dielectric constant of 9.93, a Q × f value of 73 000 GHz, and a τ f value of –68.7 ppm/ °C. What is more, the ZnGa 2 O 4 ceramics displayed a stable quality factor in the high temperature region (1400–1500 °C) due to the unique frame-structured ZnGa 2 O 4 particles. Therefore, they can be regarded as potential candidate materials for millimeter-wave device.
研究领域:
材料科学
·
微波工程
·
化学合成
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 102
·期 7
·4092-4102
·
IF 2.956
Yunhui Zhang,Haitao Wu
La 2 (Zr 1− x Ti x ) 3 (MoO 4 ) 9 (0 ≤ x ≤ 0.1) ceramics were prepared by the traditional solid-state reaction method. XRD analysis showed that La 2 (Zr 1− x Ti x ) 3 (MoO 4 ) 9 (0 ≤ x ≤ 0.1) ceramics belonged to a trigonal system. Based on the chemical bond theory, the consequences of bond energy, bond ionicity, lattice energy, and thermal expansion coefficient of ceramics on microwave dielectric properties were discussed. As Ti 4+ addition was increased, the reduction in dielectric constant was ascribed to the fact that the polarizability of Ti 4+ is smaller than Zr 4+ , and the downward trend was related to the bond ionicity. Besides, the tendency of Q·f value depended on the packing fraction and the lattice energy. The improvement in τ f value, the increase in bond energy, and the decrease in the coefficient of thermal expansion were all correlated. The far-infrared spectra implied that the absorptions of structural phonon oscillation were the main reason for the maximum polarization contribution. La 2 (Zr 0.92 Ti 0.08 ) 3 (MoO 4 ) 9 ceramics sintered at 750°C for 4 hours exhibited the best dielectric properties ( ε r = 10.33, Q·f = 80 658 GHz, and τ f = 3.48 ppm/°C).
研究领域:
材料科学
·
陶瓷工程
·
电气工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）