JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Chen-Hua Lou,An-Nan Chen,Lu Lu,Jia-Min Wu,Li-Jin Cheng,Rong-Zhen Liu,Shuang Chen,Ying Chen,Yu-Sheng Shi,Chen-Hui Li
MgO-doped Ba 0.67 Sr 0.33 TiO 3 (BST) ceramics with uniform microstructure and enhanced dielectric loss were prepared by direct coagulation casting via high valence counter ions (DCC-HVCI) method. MgO was utilized as acceptor dopant as well as coagulating agent to release Mg 2+ solidifying ceramic suspensions. Effect of sintering temperature and MgO doping content on microstructure and dielectric properties of BST ceramics was investigated. It was found that the loss tangent value (tan δ) decreased remarkably from 0.025 to 0.004 with increasing MgO concentration from 0.5 to 1.5 mol%. The 1.5 mol% MgO-doped BST ceramics processed high density of 99.5% and tan δ of 0.004 which is improved by 150% compared with that of dry-pressed samples. This improvement can be attributed to the ubiquitous distribution of MgO in BST ceramic matrix leading to the enhanced inhibitive effect. This paper provides a novel facial route to prepare high-performance functional ceramics with high reliability and low cost.
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
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Gang Liu,Jia Dong,Leiyang Zhang,Linjiang Yu,Fangbin Wei,Yang Li,Jinghui Gao,Jinzhu Hu,Yan Yan,Quan Li,Kun Yu,Li Jin
A B-site acceptor doping strategy has been employed to fabricate Na 0.25 Sr 0.5 Bi 0.25 TiO 3 (NSBT- x M) relaxor dielectric ceramics for the purpose of obtaining predominant energy storage properties for pulsed power capacitor applications. MgO was selected as the acceptor additive, and the corresponding ceramics were designed and prepared by traditional preparation method of electronic bulk ceramic. The influence of MgO on the micro structure, surface micromorphology, the variation of dielectric properties and storage of electrical energy, and also the mechanism of the NSBT- x M samples were deeply and systematically studied. The substitution of Ti 4+ by Mg 2+ at B-site induces point defects companied with defect diploe P D , which influences the electrical properties dramatically. Appropriate amount of MgO can significantly increase the electrical breakdown strength and reduce P r , which is conducive to the improvement of energy storage performance. Particularly, the NSBT-0.25 M sample exhibits both high W rec (2.06 J/cm 3 ) and excellent efficiency (84%) spontaneously. It also exhibits fantastic frequency stability, fatigue endurance, and excellent charge and discharge performance.
研究领域:
材料科学
·
电子陶瓷
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Zhidong Xia,Bin Meng,Heng Zhang,Qian Zheng,Wenke Liang,Xinyu Ping
Ce 0.8 Sm 0.2 O 1.9 (SDC)-xMgO (x = 0, 5, 10, 15, and 20 mol%) composite powders were synthesized by a sol-gel method and then densified by spark plasma sintering (SPS) to investigate the effects of MgO additions on the electrical conduction behavior of CeO 2 -based ceramics. The microstructure and electrical performances of the SDC-MgO composite ceramics were characterized and measured by XRD , SEM, TEM, EDS and EIS . Results show that the second phase of MgO segregates at the grain boundaries of SDC when its content is higher than 5 mol% in the ceramics. The SPS process accelerates the formation of MgO lamellar grains with incomplete crystallization. As the MgO content rises from 0 to 20 mol%, the grain boundary and total electrical conductivities first increase and then decrease, and the SDC-5%MgO sample exhibits the highest total conductivity, i.e., 2.76 × 10 −2 S/cm at 650 ° C, which is 9.65% higher than that of pure SDC.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Xuechen Huang,Hanxing Liu,Hua Hao,Shujun Zhang,Yue Sun,Wenqin Zhang,Lin Zhang,Minghe Cao
MgO-doped 0.97BaTiO 3 –0.03BiYO 3 (0.97BT–0.03BY) polycrystalline ceramics were prepared by the solid-state sintering method. Then the structural, dielectric and resistant properties were investigated as functions of MgO addition. Microstructure was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). The results show that Bi 3+ , Y 3+ and Mg 2+ ions exhibit nonuniform distribution behavior in BT–BY ceramics, demonstrating the existence of a “core–shell” structure, which plays important roles in the capacitance-temperature characteristics, where 0.97BT–0.03BY with the addition 2.2–2.8 at% MgO meets the Electronic Industries Association (EIA) X8R (−55 to 150 °C, ΔC / C 25 °C =±15% or less) specification. Moreover, the fine-grained samples with core–shell structure show much higher bulk resistance than the coarse-grained samples over the studied temperature range, which is attributed to the higher proportion of grain boundaries and the lower concentration of the effective acceptor.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2018
·Vol. 5
·期 3
·036305
·
IF 1.151
Gang Liu,Ziyang Wang,Leiyang Zhang,Wenjing Shi,Jiayi Jing,Yi Chen,Hongbo Liu,Yan Yan
MgO doped NBT-BT ceramics were prepared by the conventional electroceramic processing. The effects of MgO on the phase, microstructures and electrical properties of NBT-BT ceramics were systematically investigated. When doping content is more than 1%, a second phase appeared, which has great effect on dielectric, ferroelectric, and piezoelectric properties, such as the TF-R peak weakened, moved to the higher temperature, and eventually disappeared. When the doping content is above 1.5%, the ceramic samples show a strong relaxation. The detailed analysis and discussion can be found within this study.
研究领域:
材料科学
·
无机非金属材料
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 29
·23116-23127
·
IF 2.779
Zhang Yu,Xiao Lei,Peng Sen,Li Qiang,Yi Tulin,Liu Weichun,Sun Yuxin
Ba[(Zn 1- x Mg x ) 1/3 Nb 2/3 ]O 3 ( x = 0 ~ 0.9) ceramics were prepared by the traditional solid-phase reaction sintering method. In this paper, the effects of MgO doping on the shrinkage, density, phase composition, crystal structure, microstructure, and microwave dielectric properties of Ba(Zn 1/3 Nb 2/3 )O 3 (BZN) ceramics were investigated. The phase constituents, crystal structure, and microstructure of the ceramics were studied by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). The results showed that Ba(Zn 1/3 Nb 2/3 )O 3 as the main phase, and the secondary phase Ba 5 Nb 4 O 15 was detected with high MgO content ( x > 0.3). However, the appearance of secondary Ba 5 Nb 4 O 15 directly led to the deterioration of the microwave dielectric properties of the samples. Ba[(Zn 1– x Mg x ) 1/3 Nb 2/3 ]O 3 ( x = 0.3) ceramics sintered at 1500 °C for 4 h possessed superior dielectric properties: ε r = 36.31, Q × f = 111,326 GHz, τ f = + 12.1 ppm/°C. Such the ceramics could be used to make dielectric resonators and stable oscillators.
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 MATERIALS SCIENCE
·
2023
·Vol. 58
·期 31
·12724-12735
·
IF 4.5
Zhang Changhai,Wang Hairui,Zhang Tiandong,Zhang Yue,Zhang Yongquan,Tang Chao
Polymer dielectric materials are attracting wide focus in electronics, but their low energy density limits miniaturization and intelligent application. In recent years, the sandwich-structured has offered an ideal way to enhance the energy storage performance of polymer materials. In this work, the symmetrically sandwich composite dielectrics were prepared, containing an outer layer of poly (vinylidene fluoride-trifluoro ethylene chlorofluoride)@titanium dioxide (P (VDF-TrFE-CFE)@TiO 2 ) and an inner layer of poly (methyl methacrylate)@magnesium oxide (PMMA@MgO). The sandwich structure can combine the advantages of the excellent breakdown strength of PMMA and the superior polarization strength of P (VDF-TrFE-CFE). Moreover, TiO 2 with a high dielectric constant further improves the polarization strength, and the insulation performance enhances by MgO with a large band gap. The experimental results show that 0.5–1–0.5 sandwich composite dielectric has the most excellent breakdown strength of 633.8 kV/mm, and a discharge energy density of 17.16 J/cm 3 with an efficiency of 70.1%. This work offers experimental guidance for the development of outstanding energy storage performance of polymer dielectric capacitors.
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
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Xiaoning Liu,Junyan Fu,Yiwei Tang,Richard L. Smith Jr,Xinhua Qi
MgO-doped ordered mesoporous carbon (OMC-MgO) was synthesized by evaporation-induced self-assembly (EISA) in one-pot with biomass-derived gallic acid instead of phenolics as carbon precursor, metal ion Mg 2+ instead of formaldehyde as cross-linking agent and F127 as template. Mg had dual roles as cross-linking agent to coordinate gallic acid-F127 micelle composites, and as promoter of active sites. With the developed protocol, MgO could be uniformly dispersed throughout the carbon skeleton during calcination at 800 °C without agglomeration. As-prepared OMC-MgO-T800 had a specific surface area of 808 m 2 /g, a perfectly-ordered mesoporous structure centered at (6–8) nm, and exhibited good performance for phosphorus removal from aqueous solutions with a maximum sorption capacity of 107 mg/g. Electrostatic attraction, ligand exchange, and Lewis acid-base interactions are the main phosphate adsorption mechanisms of the developed MgO-doped OMC adsorbents. The as-prepared mesoporous carbon materials are highly selective for phosphorus adsorption from aqueous streams and are reusable and recyclable. This work proposes a green protocol to synthesize OMC-metal oxide composites that is widely applicable to wastewater treatment and technological areas in catalysis and energy storage.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 107
·期 1
·132-143
·
IF 3.9
Milad Kermani,Jinghua Wu,Zexiao Liu,Fei Zuo,Hua-Tay Lin,Chunfeng Hu,Salvatore Grasso
This work examines the impact of sintering thermal history on kinetics of grain growth for 1264 ppm (0.1 wt%) MgO-doped alumina. Results suggest that sintering with a high heating rate in the order of ∼10 3 °C min −1 retards grain growth rate. By contrast, a slow heating rate of 5°C min −1 resulted in an increase in grain growth constant by a factor of ∼4. The segregation of Mg to grain boundaries, favored by short sintering duration, is considered to be one of the possible factors contributing to the retarded grain growth rate for the rapidly heated compacts. Furthermore, it is proposed that the simultaneous combination of retarded grain boundary migration rate and limited surface-diffusion-driven grain coarsening, promoted by rapid heating, enables pressure-less fabrication of translucent alumina without a need for vacuum or hydrogen atmosphere. In fact, it is demonstrated that weakly translucent alumina can be produced at relatively low temperatures of 1475–1550°C by sintering with a high heating rate (herein, ∼10 3 °C min −1 ) in ambient atmosphere.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Hongyu Ding,Yujie Yang,Hao Li,Zhenyu Zhang,Zhihao Geng
High-entropy alloys (HEAs) demonstrate exceptional potential as electromagnetic wave absorbers owing to their tunable electromagnetic properties and compositional adaptability. Here, we investigate FeCoNiCrX (X = Cu, Mn, Mo, Al, Y) high-entropy alloys synthesized by vacuum induction melting-gas atomization. The FeCoNiCrMn system shows optimal microwave absorption performance, achieving a minimum reflection loss (RL) of −37.39 dB at 16.32 GHz (5.5 mm thickness) and an effective absorption bandwidth (EAB < −10 dB) of 1.52 GHz (16.48–18 GHz) at 5 mm. Surface engineering through MgO incorporation (1.0 wt%) further improves impedance matching, yielding a composite with RL min = -35.13 dB at 13.76 GHz (2 mm thickness) and 84 % broader EAB (2.8 GHz, 13.52–16.32 GHz) compared to pristine HEAs. The enhancement results from optimized dielectric-magnetic coupling and interfacial polarization, providing a strategic approach for designing thickness-adaptive microwave absorbers.
研究领域:
材料科学
·
电磁波吸收
·
合金工程
·
微波技术
✓ 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）