Crystals
·
2023
·Vol. 13
·期 7
·1005
·
IF 2.7
Zhiwei Liu,Guanlong Li,Yan Zhao,Xiangbao Chen
The rapid development of electronic technology has brought convenience and efficiency to the lives of modern people, while emphasizing the need for novel materials with designability and excellent dielectric properties at the same time. In this work, Ti3C2TxMXene nanosheets (MNSs) underwent NH3·H2O solvothermal treatment at temperatures of 40 °C, 60 °C, 80 °C, 100 °C, 120 °C, 140 °C, 160 °C, and 180 °C. The changes in the surface groups and dielectric properties after the solvothermal treatment were studied. The solvothermal treatment increased the proportion of surface -OH groups, which was beneficial to the permittivity of the MNSs. However, as the treating temperature increased, the amount of -OH on the surface of the MNSs showed a reducing trend, according to XPS spectra. As the treating temperature rose from 40 °C to 80 °C, the real part of the permittivity of MNS sample showed a significant decrease, eventually remaining approximately stable in the 80 °C to 180 °C samples. The results of electromagnetic characterization were in line with the group proportion, as determined via the XPS O1s spectra, supporting the previous conclusion that the -OH group played an important role in the permittivity.Keywords:NH3·H2O solvothermal;end groups;dielectric property;2D nanosheets
研究领域:
材料科学
·
纳米技术
·
电子学
✓ 已验证
产品关联
DOI
高影响因子
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 THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Qi Li,Jianliang Xie,Jin Hu,Xin Wang,Chengyong Yu,Shaoliang Jiang,Peng Liu,Chengli Sun,En Li,Longjiang Deng
The dielectric layer plays a key role in regulating electromagnetic wave broadband scattering based on meta-surface technology. Herein, the physical properties of composite powder, prepared by spray drying of CaO-B 2 O 3 -SiO 2 (CBS) glass-ceramic powder and Al 2 O 3 in different mass ratios, are systematically investigated. Meanwhile, a high enthalpy atmospheric plasma spraying equipment is utilized to prepare CBS/Al 2 O 3 composite coatings , and the morphology, physical properties and dielectric properties of the composite coating are analyzed. The XRD and DSC data of the composite coating reveal that the crystallization behavior of β-CaSiO 3 and CaB 2 O 4 gradually disappear with the increase of Al 2 O 3 content. Hence, only CaAl 2 Si 2 O 8 phase is observed during heat treatment. The experimental results confirm that the dielectric properties of CBS/Al 2 O 3 composite coating conform to the rule of mixture for composite materials. Also, the dielectric properties are affected by porosity and crystallization rate.
研究领域:
材料科学
·
电磁工程
·
涂层与薄膜
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 19
·1-8
·
IF 2.8
Yan Shuai,Hu Wencai,Wang Sen,Liu Gaobin
In this paper, Sr-doped BaTiO 3 nanoparticles were synthesized via electrochemical method, leading to the successful preparation of Ba 0.67 Sr 0.33 TiO 3 (BST) powders. The phase composition and microstructure of the powders were characterized using X-ray diffraction small angle X-ray scattering, scanning electron microscopy (SEM), and transmission electron microscopy. The results show that the average grain size of the nanoparticles is in the range of 10–20 nm, and the particles with good crystallinity are obtained under the environment of 3 mol.L −1 NaOH concentration. Sintering at 1250 ℃ for 3 h yields nanoscale BST ceramics with a dense structure and an average grain size of about 300 nm. These fine-grained ceramic samples exhibit superior temperature stability compared to relatively coarser BST ceramics. Furthermore, due to their nanoscale grain size, extensive phase transitions result in a low dielectric constant as observed from the dielectric property data. This work presents a novel approach for preparing nanoscale powders and homogeneous ceramics applicable in various electronic applications.
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
International Journal of Applied Ceramic Technology
·
2024
·Vol. 21
·期 5
·3422-3434
·
IF 1.8
Zhiyuan Ma,Qingqing Yang,Bin Meng,Xinyu Ping,Xiaoyu Pan,Congcong Fang
A series of (Ba 0.2 Sr 0.2 Na 0.2 Ca 0.2 La 0.2 )(Zr x Ti 1- x )O 3 (BSNCLZ x T 1- x ) ( x = 0, 0.05, 0.1, 0.15, and 0.2) high-entropy ceramics were prepared in forms of bulks and thin films by conventional sintering and spin-coating, respectively. All ceramic bulks and thin films are composed of a single perovskite-structured solid solution. The introduction of the Zr element reduces the dielectric loss of bulks and thin films and improves the frequency stability of the dielectric constant. The ceramic bulks have a higher dielectric constant and lower loss than their corresponding thin films. As x rises from 0 to 0.2, the breakdown strength E b of the ceramic bulks increases from 209 to 327 kV/cm, and that of thin films enhances from 890 to 1770 kV/cm. The bulks and thin films of BSNCLZ 0.1 T 0.9 possess the maximum recoverable energy density W rec (0.82 and 3.48 J/cm 3 ) and energy storage efficiency η (95.8% and 86.8%).
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
·
2017
·
IF 3.454
Atta Ullah,Hanxing Liu,Hua Hao,Javed Iqbal,Zhonghua Yao,Minghe Cao
(1- x )Mg 0.90 Ni 0.1 SiO 3 - x TiO 2 ( x = 0, 0.01, 0.03, 0.05) ceramics were successfully formed by the conventional solid-state methods and characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), and their microstructure and microwave dielectric properties systematically investigated. It was observed that when TiO 2 content increased from 0 to 5 wt%, the Q u f o of the sample decreased from 118,702 GHz to 101,307 GHz and increases the τ f value from −10 ppm/°C to +3.14 ppm/°C accompanied by a notable lowering in the sintering temperature (125 °C). A good combination of microwave dielectric properties (ε r ∼ 8.29, Q u f o ∼ 101,307 GHz and τ f ∼ −2.98 ppm/°C) were achieved for Mg 0.90 Ni 0.1 SiO 3 containing 3 wt% of TiO 2 sintered at 1300 °C for 9 h which make this material of possible interest for millimeter wave applications.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 109
·108028-108033
·
IF 3.289
Yu-Ling Liu,Zhongxia Wang,Xiang-Bin Han,Yu-Ling Sun,Donald E. Pryor
A new thiourea-based supramolecular compound (TA)[(TU)2Cl] (1, TA = thiazolium, TU = thiourea) has been successfully synthesized and systematically characterized, including differential scanning calorimetry (DSC), variable-temperature structural analysis and dielectric measurements. 1 undergoes a structural phase transition at 213.7 K (Tc), accompanied by distinct switchable dielectric anomalies. The TA cation is disordered over four equivalent positions above the Tc and becomes less-disordered over the two equivalent positions below the Tc. The structural relative disorder-order transition of the TA cation contributes to the switching of the dielectric constant between high- and low-dielectric states. Supramolecular inclusion compounds designed with dynamic components have been proved to be a good strategy for searching for new phase transition and switchable dielectric materials.
研究领域:
材料科学
·
晶体学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Xiaoyi Gao,Lianmeng Zhang,Chuanbin Wang,Qiang Shen
Textured Bi 5 Ti 3 FeO 15 (BTFO) ceramics were prepared by molten salt synthesis at 850 °C followed by plasma activated sintering at 800 °C. The structure and the anisotropic electrical and magnetic properties of the ceramics were investigated. The textured BTFO ceramics exhibited [001] preferred orientation with a high degree of texture fraction (Lotgering factor is 0.82), as confirmed from XRD patterns, FE-SEM and TEM micrographs. The anisotropic dielectric relaxation and conduction characteristics along the parallel and perpendicular directions were investigated using the dielectric and impedance spectroscopies. The grain boundary along the parallel direction had a similar value of capacitance to that of grains, whereas the grain boundary along the perpendicular direction dominated the resistive component. The magnetic performance along the perpendicular direction (H c ∼ 32.5 Oe) was better than that along the parallel direction (H c ∼ 17.6 Oe). These results could be useful for enhancing the electrical and magnetic properties of BTFO by texturization.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 7
·3949-3957
·
IF 3.108
Enjie Yu,Qilong Zhang,Nuoxin Xu,Hui Yang
In this study, self-assembly flower-like TiO2 (F-TiO2) particles with an average diameter of 400 nm are synthesized via a facile one-pot solvothermal method. P(VDF-HFP)-based composites with F-TiO2 particles of different volume ratio as fillers are prepared. Microstructure and thermal analyses confirm that F-TiO2 does not change the crystallization process of the polymer matrix, but disrupts the crystallization degree of P(VDF-HFP). Dielectric properties measured at various frequencies and temperatures indicate that the addition of the F-TiO2 fillers enhances the dielectric constant of the composites, while the dielectric loss and electric conductivity do not significantly increase. The dielectric permittivity of the polymer nanocomposites is enhanced by 200% over that of the P(VDF-HFP) matrix at a filler content of 20 vol% while maintaining a rather low dielectric loss (0.043 at 1 kHz). Especially, the F-TiO2/P(VDF-HFP) composites exhibit low electric conductivity (≤10−11 S cm−1) at low frequencies. All the improved performances suggest an easy method to fabricate nanocomposites having potential electrical applications.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
Crystals
·
2022
·Vol. 12
·期 4
·512
·
IF 2.67
Zhijian Wang,Feng Pan,Lanlan Liu,Qifeng Du,Ruitao Tang,Jun Ai,Hong Zhang,Ying Chen
Mg2SiO4holds promise for its application in the microwave communication field due to its low dielectric constant and highQ×fvalue. However, its high negativeτfand high sintering temperature limit its application in low-temperature co-fired ceramic (LTCC) devices. In this work, Li2TiO3and CaTiO3were introduced to improve theτf, and LiF was chosen to decrease the sintering temperature. According to XRD patterns and SEM micrographs, the ceramic systems displayed a complex-phase structure, and the microstructure was densified when CaTiO3was added. All of the relative densities, dielectric constants, andQ×fvalues first increased and then decreased as the sintering temperature increased. The MLLC11.5 ceramics sintered at 800 °C could be obtained with the highestQ×fvalue of 54,581 GHz (at 8.06 GHz),εrof 14.13, andτfof + 5.81 ppm/°C. Furthermore, it was proven that the MLLC11.5 powders could be co-fired without any reaction with Ag powders at 800 °C, indicating its potential for LTCC application. The MLLC11.5 composition was used to prepare a GPS antenna and showed good prospects for its application in electronic communications.Keywords:Mg2SiO4-Li2TiO3-LiF-CaTiO3ceramics;structure;microwave dielectric property;LTCC;antenna
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2022
·Vol. 41
·期 2
·288-296
·
IF 3.815
Tan Wan-Yi,Jian Ling-Feng,Chen Wei-Peng,Zhang Yong-Wen,Lu Xiao-Chuang,Huang Wan-Jun,Zhang Ji-Sheng,Wu Jing-Wu,Feng Jun-Li,Liu Yi-Dong,Cui Ting-Ting,Min Yong-Gang
Modified polyimides (MPIs) show great potential towards 5G communication applications, due to its excellent thermal stability, mechanical property and chemical stability as compared to most of polymers. Introducing fluoride groups or porous structure is favorable to ultra-low dielectric constant ( D k ) and dielectric loss ( D f ). However, the cost of the fluorinated MPIs is high and their synthetic processes are complicated, and porous MPIs suffer poor mechanical properties. Also, increasing the fraction of free volume is a very effective way to lower D k through introducing more ultra-low- D k air component. However, most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D f , hindering the application of MPIs in high-speed communication devices. Thus, it is highly desirable to develop intrinsic ultra-low- D k / D f MPIs at high frequency with less fluoric groups and nonporous structure. Herein, we introduce a facile and effective strategy to lower D k and D f through introducing rigid and large sterically hindered aromatic groups into MPIs. On the one hand, their large steric hindrance effect leads to low D k by increasing intrinsic free volume. On the other hand, the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D f by inhibiting dipole orientations. Based on this strategy, the spirobifluorene groups are preferred. The as-prepared MPIs show excellent dielectric performance with low D k of 2.74–2.76 and low D f of 0.00599 at 10 GHz, to some extent, exceeding the multiple fluorinated MPI with D k / D f of 2.67/0.00663 at 10 GHz.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Haipeng Dong,Bo Yang,Yin Guo,Khegay Lyubov Nikolaevna,Ming Yan,Li Song,Baikang Zhu,Zhi Li,Yingxue Lin,Shaohua Chai,Lu Zhang,Hengcong Tao
Regulating the dielectric properties of base stations is crucial for advancing 5G technology. This study presents the preparation of a series of graphene/polypropylene (PP) composites by blending various types and concentrations of graphene with PP using a melt blending process. The effect of different graphene types (graphene oxide, multilayer graphene, and exfoliated graphene) and concentrations (0.1, 0.5, 1, and 2 wt%) on the composites was characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC), impedance analyzer, rotational rheometer, and thermal gravimetric analyzer (TGA). Results show that high shear force and temperature during preparation ensure the mechanical and thermal properties of the composites. Specifically, the permittivity decreased by up to 18% with the incorporation of 1% multilayer graphene (MGE). The optimal performance was achieved with MGE compared to graphene oxide (GO) and exfoliated graphene (GE), as the composites exhibited enhanced mechanical strength, thermal stability, and lower permittivitys. This work suggests significant application prospects for PP composite materials in the 5G field due to the excellent characteristics of graphene. Highlights Graphene significantly reduces the permittivity of polypropylene. Strong interfacial bonding exists between moderate amounts of graphene and PP. Graphene boosts substrate crystallization to reduce permittivity. Composite permittivity rises with filler's permittivity increase.
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
危险品化学品经营许可证（带存储）