Journal of Materiomics
·
2023
·
IF 9.4
Chongsheng Wu,Kui Liu,Honglan Lai,Fang Xu
Herein, the sintering behavior and dielectric properties of Ta 5+ -doped Li 3 Mg 4 NbO 8 ceramics were investigated by solid-phase reactions in combination with first-principles calculations. In particular, Li 3 Mg 4 Nb 0.96 Ta 0.04 O 8 illustrates the best dielectric properties after sintering at 1,175 °C with ε r = 13.71 ± 0.20, Q × f = (132,112 ± 2,391) GHz (increased by 25%) and τ f = (25.07 ± 1.36) × 10 −6 °C −1 . The non-intrinsic factors reflect that a small amount of Ta 5+ doping produces a secondary phase, increased densification, and grain size, all of which optimize the dielectric properties. The dominant intrinsic factors indicate that the increase in bond ionicity, the greater polarization of Ta 5+ , and the blueshift of the Raman characteristic peak all lead to an increase in ε r . The increase in lattice energy and the decrease in the damping behavior of the Nb/Ta-O bond vibrations lead to an increase in Q × f . The weakening of the Nb/TaO 6 octahedral distortion leads to an optimization of τ f . The modified Li 3 Mg 4 Nb 0.96 Ta 0.04 O 8 ceramics have promising applications in microwave communications.
研究领域:
材料科学
·
陶瓷
·
介电材料
·
微波工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Rengang Shi,Shengkai Zhu,Raz Muhammad,Tao Zhou,Bing Liu,Minmin Mao,Dawei Wang,Kaixin Song
In this work, spinel-structured MgAl 2- x (Zn 0.5 Mn 0.5 ) x O 4 (0 ≤ x ≤ 0.08) single-phase ceramics were prepared through a solid-state reaction route. The substitution of (Zn 0.5 Mn 0.5 ) 3+ for Al 3+ at the octahedral site affected the degree of inversion of A/B lattice sites, bond length/strength/valence, and covalency of metal-oxygen bond in the tetrahedron and hence microwave dielectric properties of MgAl 2 O 4 . The variation in ε r and tanδ of ceramics is investigated in the millimeter wave-terahertz frequency band by combining infrared reflection spectrum and terahertz time-domain spectroscopy. A high Q × f value of 111,010 GHz @ 12.01 GHz, low ε r = 8.3, and slightly lower τ f = −60 ppm/°C is obtained for MgAl 1.98 Zn 0.01 Mn 0.01 O 4 ceramics, which is tuned by adding a small amount of SrTiO 3 . The composite ceramics exhibited a near-zero τ f (2.8 ppm/°C), high Q × f (55,400 GHz @ 11.15 GHz), and low ε r (= 8.5), showing a great potential application prospect for 5G/6G wireless communication.
研究领域:
材料科学
·
电子陶瓷
·
电磁波通信
·
固体物理
·
无机非金属材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yiming Zhao,Han Xv,Xuan Miao,Kaizheng Gao,Wenting Zhou,Lijuan Liu,Hongjun Ji,Mingyu Li,Yufeng Li
This study presents the development and optimization of cordierite/Bi 2 O 3 -ZnO-B 2 O 3 -SiO 2 (BZBS) glass composites for low-temperature co-fired ceramic applications, targeting a low dielectric constant and low dielectric loss, which are critical for 5G communication devices. The research employs an internal standard method based on Rietveld refinement to precisely analyze the phase composition under varying sintering temperatures, thereby uncovering the effects of reaction products and residual glass phases on the composite’s properties. A key finding is that sintering at 750 °C yields a relative density of 77.83 % and a CTE of 3.49 ppm/°C, closely matching that of silicon. This optimized process achieves an ultra-low dielectric constant and low dielectric loss ( ε r = 3.97, tan δ = 0.011, τ f = -38.17 ppm/°C @1 MHz, ε r = 2.79, tan δ = 0.005 @1 GHz). Additionally, three polarization relaxations- α , β and γ -were identified, providing insights into frequency-dependent dielectric behavior, which is essential for high-frequency applications. These results suggest that the optimized composite offers a balanced combination of dielectric stability, low loss, and thermal compatibility, making it a promising candidate for high-frequency LTCC substrates in next-generation microwave communications.
研究领域:
材料科学
·
陶瓷
·
电子材料
·
微波工程
·
通信技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Wen-Bo Li,Li-Xia Pang,Xiao-Long Wang,Wei-Guo Liu,Xiaogang Yao,Huixing Lin,Jin-Chao Miao,Di Zhou
This study examines the microwave dielectric properties of the Na 2 O–Bi 2 O 3 –Ln 2 O 3 –MoO 3 (Ln = Sm and Y) system, synthesized via a solid-state process at ultra-low sintering temperatures ranging from 600°C to 660°C. The X-ray diffraction and Rietveld refinement results suggested that a tetragonal sheelite phase was found in the x Na 5 Bi(MoO 4 ) 4 –(1− x )Na 5 Ln(MoO 4 ) 4 (0.05 ≤ x ≤ 0.20) ceramics. Scanning electron microscopy (SEM), backscattered electron image (BSE) and energy dispersive spectrometer (EDS) results indicated that the complex substitution of Bi 3+ produced a significant effect on the microstructural morphology. Besides, the substitution of Bi 3+ for (Sm 0.3 Y 0.7 ) 3+ effectively reduced the sintering temperature to 630°C. The variation of theoretical dielectric polarizabilities (α theo. ), the polarizability density (α theo. / V m ), the observed dielectric constant (ε r ), theoretical dielectric constant (ε theo. ), packing fraction (PF) values, and bond valence ( V i ) as a function of x value were investigated, which was helpful for understanding microwave dielectric properties. The ceramic composition 0.1Na 5 Bi(MoO 4 ) 4 –0.9Na 5 Ln(MoO 4 ) 4 sintered at 630°C for 2 h demonstrated the best microwave dielectric properties, exhibiting a ε r ∼ 9.3, Q × f value of about 31,200 GHz (at 11 GHz) and a temperature coefficient (τ f ) of −41.3 ppm/°C. Both XRD and EDS results indicated that the 0.1Na 5 Bi(MoO 4 ) 4 –0.9Na 5 Ln(MoO 4 ) 4 ceramic was chemically compatible with Ag at its sintering temperature (630°C). The x Na 5 Bi(MoO 4 ) 4 –(1− x )Na 5 Sm 0.3 Y 0.7 (MoO 4 ) 4 (0.05 ≤ x ≤ 0.20) ceramics in the Na 2 O–Bi 2 O 3 –Ln 2 O 3 –MoO 3 (Ln = Sm and Y) system are promising candidates for 5G and its successor 6G mobile communication technology.
研究领域:
材料科学
·
电子陶瓷
·
微波通信
✓ 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）