CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Jin Wang,Zhenjun Qing,Xin Zhou,Huapeng Zou,Haiyan Li,An Liu,Shumin Duan,Yingxiang Li
MnMoO 4 ceramic was prepared using solid-state reaction method. XRD and Rietveld refinement results confirmed the formation of a single phase of MnMoO 4 with monoclinic structure of C 2/ m space group. Excellent microwave dielectric properties , including ε r = 9.32, Q × f = 56,230 GHz, and τ f = −62.32 ppm/°C, were achieved for the resulting MnMoO 4 ceramic at 925 °C, which had a relative density of 97%. The dielectric polarization and packing fraction were closely related to the dielectric constant and quality factor of MnMoO 4 ceramics, respectively. Furthermore, our P–V-L analysis demonstrated that the ionicity, lattice energy, and bond energy of chemical bonds were all dominated by the Mo–O bond, which had a greater influence on microwave dielectric properties than the Mn–O bond. This finding was confirmed using Raman spectroscopy , which revealed that [MoO 4 ] tetrahedron vibrations predominated Raman vibrations, supporting the P–V-L theory. Additionally, the chemical compatibility of the MnMoO 4 ceramic with Ag co-firing was explored to investigate potential technological applications.
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
·
2023
·
IF 5.2
Zitao Shi,Zixuan Fang,Shuren Zhang,Bin Tang
Monoclinic Sm 2 O 3 ceramics were prepared using the conventional solid-state sintering method. The influences of sintering temperature on structure, morphology, and performance of Sm 2 O 3 ceramics were studied systematically. The excellent microwave dielectric properties ( ε r = 21.95, Q × f = 47,000 GHz, and τ f = +30.15 ppm/°C) were achieved in Sm 2 O 3 ceramic sintered at 1550 °C for 4 h. Interestingly, varying degrees of cracking were observed after the sintered samples were placed for a short time, with the extent depending on the sintering temperatures. The reasons for cracking were analyzed through chemical bond characteristics and microstructure. The analysis of bond valence and microstructure revealed that Sm 2 O 3 ceramics sintered at higher temperatures exhibited larger bond strain index, global instability index, and interplanar spacings. These results suggest that the cracking of Sm 2 O 3 ceramics originates from inner stress resulting from structural variations caused by variations in sintering temperatures. The effect of MgO addition on microwave dielectric properties and stability of Sm 2 O 3 ceramics was also investigated. Phase identification and elemental distribution indicated that MgO existed as a secondary phase. The Sm 2 O 3 ceramic with 20 wt% MgO addition exhibited optimal microwave dielectric properties: ε r = 17.72, Q × f = 61,100 GHz, and τ f = +2.4 ppm/°C. Importantly, cracking was not observed when MgO addition amounts were 5 wt% or higher. The attractive microwave dielectric properties and favorable stability confirm the possibility of the 5G applications for Sm 2 O 3 /MgO composite ceramics.
研究领域:
材料科学
·
电子材料
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Jing Yang,Yun Zhang,Xiaoning Li,Xinghua Zhu,Shihua Ding,Wenjie Zhou,Tianxiu Song
BaSi 2- x Al x O 5- x /2 ( x = 0-0.05) low-dielectric ceramics were prepared by the solid-phase method. The effects of heterovalent ion substitution on the crystal structure and microwave dielectric properties were studied. X-ray (XRD) diffraction revealed that they formed single-phase solid solution with orthorhombic structure. Appropriate amount of Al 3+ doping decreased the sintering temperature from 1225 °C to 1150 °C. The change in dielectric constant ( ε r ) resulted from the combined effects of the ionic nature of chemical bonds ( f i ave ) (internal factor) and the relative density (external factor). Si-O bonds contributed more significantly to the ceramic dielectric polarization. The increase in packing density and lattice energy ( U Total ) enhanced the quality factor ( Q×f ), which nearly tripled compared with the undoped case. The resonant frequency temperature coefficient ( τ ƒ ) was dominated by oxygen bond valence ( V o ). When sintered at 1150 °C for 4 h, BaSi 1.98 Al 0.02 O 4.99 exhibited optimal performance: ε r = 7.56, Q×f = 41,878 GHz, τ f = -17.65 ppm/°C. This study offered a new approach to modifying BaSi 2 O 5 ceramics.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Zhenjun Qing,Xin Zhou,Huapeng Zou,Haiyan Li,Yingxiang Li
Ca 1-x Zn x V 2 O 6 (CZVO) ceramics were successfully synthesized using the solid-state reaction method, confirming the presence of only monoclinic CaV 2 O 6 phase through XRD analysis. Introduction of Zn 2+ increased the ε r by modifying the polarization. The Q × f was found to be influenced by packing fraction, while the τ f value was affected by the distortion of [CaO 6 ] octahedra. Investigation of chemical bonding theory revealed a close relationship between the ionicity of the V-O bond and the ε r . Optimization of the Q × f value involved increasing the lattice energy, while improving τ f required strengthening the bond energy. Raman spectroscopy showed a negative correlation between the Q × f and the FWHM of the corresponding Raman peak. Ca 0.91 Zn 0.09 V 2 O 6 ceramic sintered at 700 °C demonstrated the following microwave performance: ε r of 10.3, Q × f of 67,850 GHz, and τ f of -57.3 ppm/°C. Co-firing results indicated poor chemical compatibility between CZVO ceramics and silver.
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
·
2024
·
IF 5.1
Lintao Liu,Ruihan Wang,Wei Du,Xiaohan Zhang,Haitao Wu,Xiaoqian Lu
The Cu 4 O(PO 4 ) 2 ceramic with triclinic structure (P-1) was successfully synthesized by hydrothermal and solid-phase reaction process. The influence of the relative density on the dielectric properties and thermal conductivity was systematically investigated. The crystal structure parameters of Cu 4 O(PO 4 ) 2 ceramics were determined using GSASⅡ software. Based on the P-V-L theory, it is discussed that the dielectric constant of Cu 4 O(PO 4 ) 2 ceramics is predominantly influenced by the bond ionicity ( f i ) of Cu-O, and the quality factor is significantly affected the P-O strongly. Concurrently, the P-O bond plays a positive role in the temperature coefficient of the resonance frequency while the Cu-O bond plays a negative role. The quality factor of Cu 4 O(PO 4 ) 2 ceramic sintered at 850 °C is 23,029 GHz, the dielectric constant is 7.54, and the temperature coefficient of resonance frequency is −103.44 ppm/°C. At the same time, the thermal conductivity of Cu 4 O(PO 4 ) 2 ceramic sheet is 0.42 W/(m∙K). The research on Cu 4 O(PO 4 ) 2 ceramic contributes to establishing a new material system for the field of low temperature co-fired ceramics.
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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 8
·4333-4341
·
IF 3.502
Zheng Jinjie,Yang Yaokang,Wu Haitao,Yuanyuan Zhou,Zhiliang Zhang
The microwave dielectric properties of Eu 2 TiO 5 ceramic prepared by a conventional solid-state method were investigated for the first time. An orthorhombic structure with Pnam space group was obtained from x-ray diffraction. On the basis of P-V-L chemical bond theory and refined lattice parameters, the bond parameters of bond ionicity, lattice energy, bond energy, and coefficient of thermal expansion of Eu 2 TiO 5 were computed. The relationship between chemical bond characteristics and microwave dielectric properties was discussed. Besides, far-infrared reflective spectra indicated the absorption of structural phonon oscillation might be the main contribution to polarization for Eu 2 TiO 5 ceramic. Eu 2 TiO 5 ceramic sintered at 1300°C for 6 hours possessed excellent microwave dielectric properties of ε r ~ 14.4 ± 0.2, Q × f ~ 21 000 ± 500 GHz, and τ f ~ −10 ± 2 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
Journal of Physical Chemistry C
·
2022
·
IF 4.177
Xiaohui Wu,Yulan Jing,Yuanxun Li,Hua Su
Here, a novel tri-rutile Ni0.5Ti0.5TaO4 ceramic configuration was first reported, and the sintering features, chemical bond theory, and microwave dielectric properties were systematically explored. Pure Ni0.5Ti0.5TaO4 ceramic with a tri-rutile structure was well sintered at 1275 °C with excellent microwave performance: εr ∼33.06, Q × f ∼14,600 GHz, and τf ∼93.95 ppm/°C. Based on the P–V–L theory, the dielectric constant was mainly affected by the formation of Ta–O bonds (∼62%) due to the larger ionic polarization and bond susceptibility. The experimental dielectric constant (33.06) was comparable to the theoretical calculation (P–V–L: 35.11). The lattice energy was also dominated by the Ta–O bond (∼71%) and the intrinsic loss properties. The τf was also affected by the [M1/M2O6] octahedral distortion. In addition, the relative density, grain size, and packing fraction also played a certain role in the microwave dielectric properties. Insights from the Raman spectroscopy revealed that the A1g mode dominated the Raman vibration at 699.44 cm–1. These results were helpful to provide ideas for novel medium dielectric constant materials and contributed to the miniaturization of microwave electronic devices.
研究领域:
材料科学
·
无机化学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Shen-Jing Ji,Dong Zhang,Nian-Tzu Suen
Transition metal-based intermetallics are promising electrocatalysts for replacing the commercial Pt metal in the hydrogen evolution reaction (HER). In this work, RENi2 and RERu0.25Ni1.75 (RE = Pr, Tb, and Er) were synthesized and their electrocatalytic HER activities were explored. Among undoped compounds, PrNi2 exhibits the best performance and requires an overpotential of 55 mV, while partially replacing Ni with Ru element (PrRu0.25Ni1.75) can greatly reduce the overpotential to 20 mV at a current density of 10 mA/cm2. Such enhancement was recognized that belongs to their extrinsic property, and their intrinsic HER activities were similar after normalizing the electrocatalytic surface area. Further investigation on ScM2 and ScRu0.25M1.75 (M = Co and Ni) suggests that doping Ru element in ScCo2 will significantly enhance antibonding character around the Fermi level (EF) and weaken hydrogen adsorption energy. On the other hand, the antibonding population for ScNi2 and ScRu0.25Ni1.75 is similar at EF, which accounts for their close intrinsic HER activities.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Zezhen Yin,Yun Zhang,Shihua Ding,Tianxiu Song,Xiaoning Li,Jiaying Dan
The solid-phase method was utilized to synthesize LiAl 1- x Be x O 2- x /2 and LiAl 1- x Ga x O 2 ceramics. By Phillips-Van Vechten-Levine (P-V-L) theory, a strong correlation between chemical bond characteristics and microwave dielectric properties was established. X-ray diffraction (XRD) analysis confirmed that all components formed single-phase solid solution with tetragonal structure. Using Be 2+ and Ga 3+ as substitutes, the differences in ionic radii produced diametrically opposite changes in cell volume. The relative density increased to 97.61 % (98.57 %) with the addition of Be 2+ (Ga 3+ ). According to the P-V-L theory, the variation of ε r was influenced by bond ionization. The introduction of different ions caused bond lengths variations, which in turn affected the lattice energy fluctuations. Importantly, this change more than doubled Q×f from 16,268 GHz to 37,015 GHz. Furthermore, the evolution of τ f can be elucidated by the bond energy. Sintered at 1250 °C, both LiAl 0.96 Be 0.04 O 1.98 and LiAl 0.98 Ga 0.02 O 2 demonstrated outstanding microwave dielectric properties, characterized by ε r = 5.83–6.08, Q×f = 32,727∼37,015 GHz, and τ f = −134.8∼-112.4 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
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Min Yang,Yong Zheng,Weimin Ding,Xuepeng Lu,Zhiyi Jiang,Bo Li,Zuowei Dong,Wei Zhou
To explore high-performance dielectric ceramics with intrinsically low sintering temperatures and low permittivity suitable for use in the microwave (MW) and terahertz (THz) ranges, Cu ions were selected to replace Zn ions in BaZnP 2 O 7 ceramics based on the considerations of ionic radius and chemical bond characteristics. Samples with moderate Cu 2+ substitution exhibited better performance than conventional ones, with a similar dielectric mechanism in both MW and THz frequency ranges. All samples of BaZn 1- x Cu x P 2 O 7 (0 ≤ x ≤ 0.1) solid solutions exhibit a single-phase with a triclinic structure ( P-1 ) when the sintering temperature is below 925 °C, while the BaCuP 2 O 7 phases form in the doped samples at 925 °C. Cu 2+ substitution improves density and enhances molecular polarizabilities and average ionicity, thereby raising the dielectric constant ε r . The substitution of Cu 2+ for Zn 2+ in BaZnP 2 O 7 ceramics shortens the chemical bonds, thus improving lattice stability and reducing the damping factor of phonon anharmonic vibrations. This, in turn, increases the Q × f values by 1.65 times and enhances temperature stability compared to conventional ceramics. The BaZn 1- x Cu x P 2 O 7 ceramics have good chemical compatibility with Cu, but react with Ag.
研究领域:
材料科学
·
陶瓷
·
介电材料
·
固体物理
·
微波技术
·
太赫兹技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Hailong Pan,Shijie Yan,Yiyun Zhang,Jialun Du,Xiaoyu Zhang,Pijun Gong,Haitao Wu,Huanrong Tian,Michael Wübbenhorst
A series of Ce 2 [Zr 1- x (A) x ] 3 (MoO 4 ) 9 (A = Sr 1/3 Ta 2/3 , Sr 1/3 Sb 2/3 ; x = 0.02, 0.04, 0.06, 0.08 and 0.10) (abbreviated as CZ 1- x T x and CZ 1- x S x ) microwave dielectric ceramics were studied systematically with respect to microstructures, sintering behaviors, crystal structures, microwave dielectric properties and infrared vibrational modes. Density measurements and scanning electron microscopy (SEM) reveal the dense and homogeneous microstructures. X-ray diffraction (XRD) results confirm the formation of solid solutions belonging to the hexagonal system with a R 3 ‾ c space group, and the lattice volume increases with raising the doping content. Furthermore, the complex chemical bond theory was used to calculate the intrinsic bond parameters, and the correlations between the microwave dielectric properties and intrinsic bond parameters were established. Finally, far infrared (FIR) spectra reveal that the main polarization contribution stems from the absorptions of the phonon oscillations in these two groups of ceramics. Typically, the optimum microwave dielectric properties are achieved for CZ 0.9 T 0.1 and CZ 0.94 S 0.06 ceramics with ε r = 10.24, Q × f = 92,009 GHz (at 9.70 GHz), τ f = −8.84 ppm °C −1 and ε r = 10.40, Q × f = 82,696 GHz (at 9.69 GHz) and τ f = −8.04 ppm °C −1 , respectively. Interestingly, the CZ 0.9 T 0.1 ceramic exhibits the maximum Q × f value in the ion doped Ce 2 Zr 3 (MoO 4 ) 9 ceramics while retaining a good τ f = −8.84 ppm °C −1 .
研究领域:
材料科学
·
陶瓷
·
介电材料
·
固体化学
·
微波工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）