CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zaizhi Yang,Xi Wang,Liang Zhang,Hailin Li,Hui Zhang,Dong Xu
(Ca, Ta) co-doped TiO 2 ceramics were successfully prepared using flash sintering technology, and the effects of oxygen vacancies on the rapid densification and giant dielectric properties were studied. The results suggest that the maximum volume fraction of oxygen vacancies in flash-sintered samples is approximately 10%. Oxygen vacancies decrease the barrier energy level of atomic diffusion and provide convenient diffusion channels, resulting in rapid densification of the sample within 24 min at 1100 °C. All flash-sintered samples exhibit high relative density, exceeding 95%. Oxygen vacancies promote the electron-pinning defect dipole effect at low temperatures. As the temperature increases, carriers such as oxygen vacancies move to the grain boundary, forming an internal barrier layer capacitance effect. The optical dielectric constant reaches 7.25 × 10 4 , and the dielectric loss drops to 0.09. Oxygen vacancy play an important role in both flash sintering technology and the giant dielectric properties of co-doped TiO 2 ceramics.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Can Qu,Yiting Long,Xuemei Zhang,Jingsong Liu,Linyu Pu,Xu Huang
In this paper, UiO-66 nanoparticles were synthesized through the hydrothermal synthesis technique. Subsequently, a series of metal-organic framework/polyvinylidene fluoride (MOF/PVDF) composite films were produced via a solution-casting approach. The dielectric properties of UiO-66/PVDF (U/P) composite are improved with the addition of UiO-66. The dielectric constant ( ɛ r ) of 20 wt% U/P composite film at 10 2 Hz is 11.20, 1.44 times that of pure PVDF film ( ɛ r = 7.78). However, the breakdown strength ( E b ) was only 95 kV mm −1 . To solve the problem of sharp decline in E b , TiO 2 with a wide band gap was introduced to form an insulating layer on the surface of UiO-66. This reduces the difference in electrical properties between the filler and PVDF, hinders the formation of the conductive path within the composite, reduces leakage current, and increases E b . Compared with the U/P composite, the ɛ r and E b of TiO 2 @UiO-66/PVDF (T@U/P) composite film are increased, and the dielectric loss (tan δ ) and leakage current density ( J ) are decreased. The energy storage density ( U e ) of 10 wt% T@U/P composite film is 4.51 J cm −3 and the charge and discharge efficiency ( η ) is 84.61% at 150 kV mm −1 . These results indicate that the dielectric properties of UiO-66 can be significantly enhanced by using titanium dioxide as an insulating layer. Highlights By introducing UiO-66, the ɛ r of PVDF material is improved. Modifying UiO-66 with TiO 2 can improve its breakdown strength significantly. The U e of the T@U/P-10 composite modified with UiO-66 is 4.51 J cm −3 .
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
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
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Haiyang Dai,Qinlong Shen,Jing Chen,Dewei Liu,Tao Li,Cui Shang,Zhenping Chen
Ceramic samples of Mn 1- x Zr x WO 4 (0.00 ≤ x ≤ 0.20) were prepared by a solid-state reaction to study changes in the structural, magnetic, and dielectric properties of multiferroic MnWO 4 caused by replacing Mn 2+ ions with Zr 4+ ions. The results indicate that Zr 4+ replacement caused lattice deformation but did not affect the monoclinic lattice structure of any of the MnWO 4 samples. The concentration of vacancies, investigated by positron annihilation lifetime spectroscopy, increased with as the Zr 4+ content x from 0.00 to 0.20. It was observed that Zr 4+ replacement enhanced the dielectric constant of Mn 1- x Zr x WO 4 but slightly increased the dielectric loss. The magnetization and transition temperatures (T AF3 and T AF2 ) of the Mn 1- x Zr x WO 4 system were increased by the Zr 4+ replacement, and the existing temperature range of the AF2 phase was extended upon the substitution of Zr 4+ for Mn 2+ . This study demonstrated that the magnetic properties of Mn 1- x Zr x WO 4 were closely related to the vacancy concentration and lattice distortion.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2025
·Vol. 17
·期 3
·339
·
IF 4.9
Yuwei Chen,Yidong Liu,Yonggang Min
This study addresses the limitations of traditional polyimides (PIs) in high-frequency and high-temperature soft electronic applications, and then introducing trifluoromethylbenzene (TFMB) into the molecular structure and employing various diamines as connecting components to solve the bottleneck. The innovative molecular design enhances thermal, mechanical, and dielectric properties, overcoming challenges in balancing these performances. The optimized fluorinated PI (TPPI50) exhibits exceptional properties, including a glass transition temperature of 402 °C, thermal decomposition temperature of 563 °C, tensile strength of 232.73 MPa, elongation at break of 26.26%, and dielectric constant of 2.312 at 1 MHz with a dielectric loss as low as 0.00676. These improvements are attributed to the unique synergy between TFMB’s fluorinated groups, which reduce molecular polarization, and the biphenyl structure, which reinforces chain stability. Compared to conventional PIs, TPPI50 demonstrates superior comprehensive performance, making it highly suitable for soft circuits, high-frequency signal transmission, and advanced applications such as wearable devices and biosensors. This study provides a robust framework for industrial applications, offering a path to next-generation soft electronics with enhanced reliability and performance.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 34
·1-13
·
IF 2.8
Xu Jialing,Jing Haofeng,Hou Xiong,Feng Hengheng,Yu Hongtao
For capacitor applications, Ba(Sm 1- x - y La x Bi y ) 2 Ti 4 O 12 dielectric ceramics with La/Bi co-substitution for Sm were prepared using the conventional solid-state method. Part of Sm 3+ was found to be replaced by La 3+ and Bi 3+ in ceramics that exhibit an orthorhombic tungsten bronze structure. As the concentration of Bi 3+ increased, a second phase of Bi 4 Ti 3 O 12 was observed. The co-substitutions could reduce the sintering temperature and effectively increase the dielectric constant from 80 to 140. The dielectric loss increased slightly with increasing La 3+ and Bi 3+ , but it still remained below 0.1% at 1 kHz. After sintering, a specific composition was achieved with x = 0.1 and y = 0.4. It has a high dielectric constant of 132, an ultra-low dielectric loss of approximately 0.06%, and excellent frequency stability. Additionally, it exhibits a capacitance-temperature change of ± 1% at 1 kHz over a temperature range of − 55 to 125 °C.
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 AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 106
·期 4
·2384-2392
·
IF 4.186
Yi Zhang,Rongxia Huang,Fan Zhang,Zhihao Liang,Tianbao Xie,Hua-Tay Lin,Yejing Dai
ZrO 2 powders of various particle sizes (0.15, 0.7, 500 µm) were used to simulate loose powder bed sintering to prepare BF–BT piezoelectric ceramics. The phase structure, dielectric properties, ferroelectric properties, and piezoelectric properties were compared with the samples sintered by the conventional powder bed method (i.e., powder of the same composition as the sample). Results showed that the use of loose ZrO 2 powder bed could improve the heat conduction rate and the sintering quality of bulk BF–BT piezoelectric ceramics. The XPS results showed that the samples sintered with 500 µm ZrO 2 powder beds had the lowest concentration of Fe 2+ , exhibited the largest piezoelectric coefficients ( d 33 = 201 pC/N). In contrast, the sample sintered with a conventional powder bed under the same sintering conditions had a piezoelectric coefficient d 33 of 156 pC/N.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
COMPOSITES COMMUNICATIONS
·
2021
·
IF 6.617
Ping Wang,Li Yang,Yiyang Zhou,Shang Gao,Tian Cao,Shaojie Feng,Pei Xu,Yunsheng Ding
Hydroxylated BaTiO 3 (BT-OH) and multiwalled carbon nanotubes (MWCNTs) were incorporated into polyamide (PA) and ethylene-vinyl-acetate-glycidyl methacrylate random terpolymer (EVA-GMA) blends by melting-blend and hot-pressing method. Compared with PA/EVA-GMA/C nanocomposites, PA/EVA-GMA/20B/C nanocomposites exhibited higher dielectric permittivity, originating from the high dielectric constant of BT-OH and remarkable interface polarization effect between polymer and two types of nanofillers. Moreover, the nonconducting BT-OH can prevent the conductive path of MWCNTs and support low loss tangent. The dielectric constant of PA/EVA-GMA/20B/4C was 31.5 at 100 Hz, approximately three times higher than that of PA/EVA-GMA, and the loss factor was only 0.18, close to that of PA/EVA-GMA. PA/EVA-GMA/20B/4C exhibited tensile strength and elongation at break of 27.7 MPa and 67.9%, respectively. The mechanical and dielectric properties of PA/EVA-GMA/20B/4C were synergistically improved.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Mengna Feng,Chunting Li,Meng He,Yumin Huang,Juhua Luo
Flexible, high- k and thermostability polymer-based dielectric composites are the core components in electrostatic capacitors and embedded devices. Herein, the dielectric polymer matrix composites are developed by embedding polydopamine (PDA)-encapsulated hydroxylated barium titanate (BTH) and molybdenum disulfide (MoS 2 ) into poly(arylene ether nitrile) (PEN) matrix. The MoS 2 /PDA@BTH-1 particles served as fillers are prepared by polydopamine deposition technology assisted with hydrogen bonding interactions. The introduction of PDA intermediate layer contributes to the construction of multiple interfaces and nanocapacitor networks, enhancing interfacial polarization. Based on this, the resulted dielectric composite with 15 wt% MoS 2 /PDA@BTH-1 loading exhibits the dielectric constant of 17.3 at 1 kHz, higher than that of 4.2 of PEN, while can maintain relatively low dielectric loss simultaneously. The possible mechanisms and synergistic enhancement effect of MoS 2 /PDA@BTH-1 particles on the dielectric properties of composites are also proposed. The results of permittivity-temperature stability show that the dielectric constant of PEN-based dielectric composites is stable when reaches 158 °C, indicating that the film can be used in capacitor at temperatures up to 150 °C, higher than that of most polymer capacitors. All in all, a feasible pathway is provided to design PEN-based dielectric composites with high- k to adopt the high-temperature environment in electrostatic capacitors and embedded devices.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR RESEARCH
·
2019
·Vol. 28
·期 4
·373-381
·
IF 1.758
Wu Xudong,Huang Jingyu,Yu Shuhui,Ruan Panpan,Sun Rong,Wong Ching-Ping
Dielectric materials with self-healing property after the occurrence of detrimental events such as tearing or scratch are highly desired, which guarantees reliability and lifetime of the electric and electronic systems. Here, a self-healing covalently bonded titanium dioxide/polyurethane (TiO 2 /PU) nanocomposite with enhanced dielectric constant was prepared by in-situ polymerization based upon Diels-Alder reaction. The PU prepolymer was prepared from TiO 2 , poly(tetramethylene glycol) and 4,4-diphenylmethane diisocyanate. Then the linking between the prepolymer and Diels-Alder adducts of bifunctional maleimide blocked by furfuryl alcohol was carried out. The in-situ polymerization method allows the TiO 2 filler, the PU polymer matrix, and the DA healing portion to be tightly connected, resulting in a stable nanocomposite system. Due to the reversibility of covalent bonds, the TiO 2 /PU nanocomposites exhibited thermal self-healing properties after being cut. The dielectric constant and loss, mechanical properties can be effectively restored to their original state after damage.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Junlei Qi,Minghe Cao,Yiying Chen,Hua Hao,Zhonghua Yao,Hanxing Liu
The effect of sintering atmosphere on the microstructure and dielectric properties of Sr 0.985 Ce 0.01 TiO 3 were investigated in this article. The sample sintered in nitrogen achieves a colossal permittivity (∼12655) and ultralow dielectric loss (0.006) at room temperature and 1k Hz. XRD results reveal that all the samples belong to P m 3 ¯ m space group and no secondary phase is detected. It can be verified by XPS measurement that the nitrogen sintered sample has the highest Ti 3+ content. Five dielectric relaxations can be observed in the dielectric spectroscopy in the test temperature range from −130–500 °C, which can be attributed to the existence of Ti 3+ ions, oxygen vacancies and the other associated defect clusters. Moreover, the off-center Ti 3+ ions make a certain contribution to the high permittivity. The ultralow dielectric loss at room temperature could be ascribed to the formation of defect clusters in the samples sintered in air and nitrogen. These defect clusters which associated with the oxygen vacancy, such as T i 3 + − V O .. − T i 3 + and V S r " − V O ¨ are able to localize charge carriers and restrain the motion and ionization of oxygen vacancies.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
SCRIPTA MATERIALIA
·
2019
·
IF 4.539
Baisheng Ma,Yan Zhu,Kewei Wang,Zhenzhong Sun,Dianguang Liu,Gang Shao,Jinling Liu,Yiguang Wang
Flash sintering method was adopted to sinter SiO 2 -coated BaTiO 3 ceramics to lower sintering temperature and shorten sintering time. The microstructure and dielectric property of BaTiO 3 with different amount of SiO 2 coating were studied. Samples can be flash sintered at furnace temperatures lower than conventional sintering temperature. Though the onset flash sintering temperature increased obviously with increasing SiO 2 content, the estimated sample temperatures were found close to each other. Samples with improved density was achieved with higher SiO 2 content, but their dielectric constant decreased. Flash sintered samples with 1.5 wt% SiO 2 addition possess a fair dielectric constant with improved density.
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）