Materials
·
2023
·Vol. 16
·期 14
·5195
·
IF 3.4
Jun Yang,Jinbiao Pang,Xiaofang Luo,Laiyuan Ao,Qiang Xie,Xing Wang,Hongyu Yang,Xianzhong Tang
This work studied the phase constitution, bond characteristics, and microwave dielectric performances of Sr2TiO4ceramics. Based on XRD and Rietveld refinement analysis, pure tetragonal Ruddlesden–Popper type Sr2TiO4ceramic is synthesized at 1425~1525 °C. Meanwhile, the microstructure is dense and without porosity, indicating its high sinterability and densification. Great microwave dielectric performances can be obtained, namely anεrvalue of 39.41, and aQ × fvalue of 93,120 GHz, when sintered at 1475 °C. Under ideal sintering conditions, the extrinsic factors are minimized and can be ignored. Thus, the intrinsic factors are considered crucial in determining microwave dielectric performances. Based on the P–V–L complex chemical bond theory calculation, the largest bond ionicity, and proportions to the bond susceptibility from Sr–O bonds suggest that Sr–O bonds mainly determine the dielectric polarizability. However, the Ti–O bonds show lattice energy about three times larger than Sr–O bonds, emphasizing that the structural stability of Sr2TiO4ceramics is dominated by Ti–O bonds, and the Ti–O bonds are vital in determining the intrinsic dielectric loss. The thermal expansion coefficient value of the Sr2TiO4structure is also mainly decided by Ti–O bonds.Keywords:Sr2TiO4;microwave dielectric properties;P–V–L complex chemical bond theory
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
·
2022
·Vol. 33
·期 27
·21976-21984
·
IF 2.779
Sha Ke,Lin Feng Li,Liu Bing,Song Kai Xin,Zhang Jia Heng
Dense (Sr 1 − x Ca x ) 2 (Ti 1 − x Sn x )O 4 ( x = 0.0, 0.05, 0.10, 0.15) ceramics were synthesized by a standard solid-state reaction method. The formation of solid-solution with an I 4/ mmm space group was revealed from the X-ray diffraction patterns and Rietveld refinement results. The variation of the microwave dielectric properties was systematically analyzed using the dielectric polarizability and complex chemical bond theory. The dielectric constant ( ε r ) was mainly determined by the ionic polarizability per unit volume. Qf value was closely associated with the increasing amount of Sr 3 Ti 2 O 7 secondary phase and the declined lattice energy. Meanwhile, the variation of Qf value was further analyzed by extrapolating the intrinsic dielectric loss from the infrared reflectivity spectra. τ f value was successfully adjusted toward zero, which could be explained by the enhanced bond energy. The optimal microwave dielectric properties were achieved at x = 0.10, with ε r = 33.6, Qf = 73,150 GHz, and τ f = 115 ppm/°C.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
C.H. Yang,H.L. Pan,Y.K. Yang,H.T. Wu
Li 2 Mg 3 Zr 1−x Ti x O 6 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) ceramics were prepared via a solid-state reaction method. Crystal structures, sintering behaviors, micro-structures and microwave dielectric properties of Li 2 Mg 3 Zr 1−x Ti x O 6 (0 ≤ x ≤ 1) ceramics were investigated by XRD , SEM and chemical bond theory. XRD results showed that a single phase with the rock-salt structure was formed in all ranges. On the basis of the Rietveld refinement and chemical bond theory, several intrinsic parameters were calculated and connections between intrinsic parameters and microwave dielectric properties were investigated. The substitutions of Ti 4+ for Zr 4+ obviously increased the relative density and improved the quality factors. Variations of ε r could be explained by changes of the polarizability. Q·f values showed the similar trend with the packing fractions, average bond valences and lattice energy of Zr–O bonds. τ ƒ values significantly correlated with the bond energy of Zr–O bonds.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 20
·8491-8501
·
IF 3.553
Zhang Yun,Ding Shihua,Li Chao,Song Tianxiu,Zhang Yingchun
A new type of ceramic, namely MnZrTa 2 O 8 , was synthesized after sintering at high temperature in this work. The possible dielectric loss mechanism was discussed by Raman spectroscopy and chemical bond theory. X-ray diffraction indicated that MnZrTa 2 O 8 formed through a reaction between ZrO 2 and intermediate MnTa 2 O 6 . After sintering at 1350 °C, a monoclinic structure with cell parameters a = 4.8370(3) Å, b = 5.7163(1) Å, c = 5.1398(5) Å, β = 91.7219° was gained for ceramic. Among all bonds, Ta–O with the greatest bond ionicity and lattice energy was the dominant factor that influenced the microwave dielectric properties. The temperature coefficient of the resonant frequency τ f changed from − 50.55 to − 41.21 ppm/ °C, which was related to the lattice energy. The effect of porosity on dielectric loss was also checked and found to be significant. MnZrTa 2 O 8 ceramic exhibited relative permittivity ε r ~ 23.0 and enhanced quality factor Q × f ~48103 GHz (at 8.97 GHz), which provided a promising candidate for electric components.
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
·
2021
·
IF 5.302
Gang Wang,Dainan Zhang,Jie Li,Liang Shi,Yan Yang,Gongwen Gan,Xiaolei Shi,Cheng Liu,Yulong Liao,Lichuan Jin,Huaiwu Zhang
Wolframite-structured Mg 1-x Ca x ZrNb 2 O 8 (0−0.1) ceramics were synthesized through a solid-state procedure. Crystal refinement indicates a pure Mg 1-x Ca x ZrNb 2 O 8 ceramic with a wolframite structure. Ca 2+ substitution led to the redshift of the Ag mode at approximately 896 cm −1 . Additionally, Ca 2+ substitution could promote grain growth and contribute to microstructure evolution from a polyhedral shape to a rod shape. According to chemical bond theory, an appropriate Ca 2+ concentration can increase Nb O bond iconicity and Nb O bond lattice energy, which contributed to the great improvement in the dielectric constant and Q × f value. Additionally, the τ f value was affected by the bond valence and thermal expansion coefficient of the Mg O bond. The Mg 1-x Ca x ZrNb 2 O 8 ( x = 0.04) ceramics exhibited great improvement in the Q × f value: ε r = 25.21, Q × f = 116,000 GHz (@7.17 GHz) and τ f = −24.4 ppm/°C, which provides enormous potential for future millimeter-wave applications.
研究领域:
材料科学
·
陶瓷工程
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Shumin Duan,Zhenjun Qing,An Liu,Haiyan Li,Yan Xue
The single-phase, cubic-structured Ba 3 La(PO 4 ) 3 ceramics were synthesized using the traditional solid-state reaction method. The ceramic sintered at 1375 °C exhibited a relative density of 95.4 %, indicative of a dense microstructure and excellent sintering characteristics. Furthermore, they displayed remarkable microwave dielectric properties : ε r = 9.54, Q × f = 32820 GHz, and τ f = −43.1 ppm/°C. In addition, the relative density is positively correlated with ε r and Q × f of ceramics. According to the complex chemical bond theory, the ionicity of the Ba/La–O bond has a more significant impact on the ε r , while the lattice energy and bond energy of the P–O bond respectively dominate the Q × f and τ f values. Moreover, the results from Raman spectroscopy indicate that several prominent Raman bands are associated with the vibration of the P–O bond. These findings suggest that Ba 3 La(PO 4 ) 3 ceramics hold promise for applications in high-frequency microwave communication.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
npj Computational Materials
·
2025
·Vol. 11
·期 1
·1-9
·
IF 11.9
Yang Lan,Zhou Xiao,Ni Xudong,Huang Li,Zeng Lianduan,Wang Zhongyang,Song Jun,Fan Tongxiang
The optical static refractive index, a critical intrinsic property of materials, plays a vital role in advanced optoelectronic applications. Accurate prediction of this index is essential for the efficient design and optimization of materials with tailored optical properties. Here, we present a robust predictive model that accurately forecasts the optical static refractive indices of complex oxides across diverse crystal structures and compositions. By leveraging chemical bond theory, our model elucidates the influence of intrinsic physical properties, including chemical bonds and d-electron bands, on the refractive index. Through rigorous analysis of 41 complex oxide systems and 5 doped systems, we demonstrate that our predictions align closely with experimental data, showcasing the model’s high accuracy and broad applicability. This work not only accelerates the development of novel materials and spectral design but also provides profound physical insights for optimizing and customizing optical properties.
研究领域:
材料科学
·
光学
✓ 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）