International Journal of Applied Ceramic Technology
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2023
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IF 2.1
Fangyi Huang,Xiaoli Tang,Qin Zhang,Xingyu Huo,Yuanxun Li,Xian Jian,Hua Su
In this study, the microwave dielectric properties of Co 2+ -substituted BaZnP 2 O 7 ceramics prepared through conventional solid-state synthesis were investigated. X-ray diffraction, Rietveld refinement, energy-dispersive spectroscopy, and Raman spectroscopy all indicated that BaZn 1− x Co x P 2 O 7 ceramics sintered at 875°C were composed of a single phase. The lattice strain and crystallite size were estimated using Williamson–Hall (W–H) method. Both the scanning electron microscopy images and density measurements showed that Co 2+ ions had an effect on the grain growth and densification of ceramics. The microwave dielectric properties were influenced by the intrinsic and extrinsic factors that varied with the increase of x value. An optimal performance ( ε r = 7.62, Q × f = 600 45 GHz, and τ f = −74 ppm/°C) was achieved at x = .01. The porosity and relative density played a significant role in the dielectric constant ε r : the denser the ceramic structure, the larger the dielectric constant. The Q × f and τ f values were negatively correlated with the full width at half maximum of the Raman vibrational peak at approximately 1049 cm −1 . Moreover, the Q × f value was improved compared to that of the undoped BaZnP 2 O 7 ceramics. Therefore, cobalt ion substitution is an effective strategy to enhance the performance of microwave dielectric ceramics.
研究领域:
材料科学
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陶瓷工程
·
固体物理
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DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
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2020
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IF 7.094
Shengdao Wang,Yanchao Yang,Yongfeng Mu,Jiyao Shi,Xin Cong,Jiashuang Luan,Guibin Wang
Carbon fiber/PEEK composites have gained significant attention in the field of continuous carbon fiber reinforced polymers (CFRPs). However, it remains challenging to improve the weak interfacial strength between carbon fiber (CF) and PEEK matrix. In this paper, strong interactions at the interface of sizing agent and carbon fiber were effectively achieved by introducing chemical bonds. Specifically, a soluble PEEK sizing agent where aniline served as pendant group and phenylacetylene served as blocking agent was synthesized. In the meantime, the phenylacetylene group was grafted on the carbon fiber surface through electroreduction . Then, the soluble sizing agent was used to size the electrochemical treated carbon fiber. After the heat treatment, chemical bonds were established by the crosslinking reaction of phenylacetylene groups existed in both the surface of carbon fiber and sizing agent. Meanwhile, the crystalline structure in the sizing layer was remained, which could improve the toughness of the interphase. As a result, the interfacial shear strength (IFSS) increased by 137.5% from 43.4 MPa of the untreated carbon fiber (U-CF) to 103.1 MPa of the reductive electrografted and coated carbon fiber (E-C-CF). The interlaminar shear strength (ILSS) also increased by 66.8% from 58.4 MPa of untreated CF/PEEK composites (U-CF/PEEK) to 97.4 MPa of reductive electrografted and coated CF/PEEK composites (E-C-CF/PEEK). The outstanding performances could be attributed to better compatibility of sizing agent and most importantly, the existence of chemical bonds between the carbon fiber and sizing agent.
研究领域:
材料科学
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复合材料工程
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DOI
高影响因子
Environmental Chemistry Letters
·
2017
·Vol. 16
·期 1
·251-264
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IF 3.594
Yein Win Thi,Wang Qun,Feng Xueying,Li Yang,Wu Xiaohong
Nanocomposites composed of two or more components with desirable performance have attracted tremendous attention, mainly due to the synergic effect between the components. The effective combination of ZnO and reduced graphene oxide would lead to ameliorate the photocatalytic performance. To enhance applicability of semiconductor photocatalytic, the composites used should be good interfacial contact governed by suitable particle size distribution. Herein we aim to fabricate the different crystallize size of ZnO nanoparticles (NPs) in ZnO–reduced graphene oxide (ZnO–rGO) nanocomposites by sonochemical synthesis and subsequent facile drying treatment method. The Zn precursor, Zn(Ac) 2 , with a plenty of functional groups, was used as a starting source for both reduction of graphene oxide and formation of ZnO on rGO sheets through chemical bonds without the addition of hazardous reducing agents. LiOH was chosen as an assistive reagent to enhance the complete reaction between Zn(Ac) 2 and GO in the formation of ZnO–rGO nanocomposites. More remarkably, drying condition has the great influence on the crystallize size of ZnO NPs in as-prepared ZnO–rGO nanocomposites. It is found that ZnO–rGO nanocomposites dried at −50 °C (freeze drying) show the highest photocatalytic efficiency in the degradation of rhodamine B (RhB) as compared to ZnO–rGO nanocomposites by other drying conditions under visible-light irradiation. Correlating the crystallize size obtained by different drying temperatures with the photocatalytic activity, it is probed that the smaller crystallize size in ZnO–rGO nanocomposites enhances the interfacial contact and a chemical bonding between rGO and ZnO NPs leading to the effective separation of electrons and holes. In addition, the O
·− 2
anion was determined to be the main active oxidant by free radicals trapping experiment and a photodegradation mechanism of ZnO–rGO nanocomposites over rhodamine B (RhB) was proposed based on our observations.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2017
·Vol. 85
·期 2
·394-401
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IF 1.575
Qian Xin,Han Huanre,Chen Yulong,Yuan Ye
Abstract In this study, an attempt is done to synthesize anatase/brookite/rutile TiO 2 nanocomposites via a simple solvothermal method with hydrochloric acid, dehydrated ethanol, and titanium butoxide in a sol−gel environment. The effect of preparation temperature on the content of each phase, crystallite size, morphology, and photocatalytic activity was systemically studied. The structures of the products prepared under different temperatures were characterized using X-ray diffraction analysis, transmission electron microscopy, Raman spectra, and BET surface area. The optical properties were measured by UV–vis diffuse reflectance spectra. Besides, the photocatalytic activities were evaluated by performing the degradation of rhodamine B azo dye under UV−vis radiation. The results reveal that the content of different phases and crystallite size can be tailored via tuning the solvothermal condition. In addition, the obtained TiO 2 nanocomposites are a kind of mesoporous materials and have large BET surface area, narrow pore size distribution, and low band gap, which exhibit excellent photocatalytic performance (of activity about 4.40 times that of Degussa TiO 2 P25). Through examining the photocatalytic stability, the obtained TiO 2 nanocomposites exhibit a very stable photocatalytic performance. Therefore, the current method to TiO 2 preparation could provide a simple and reliable route for developing photocatalytic materials with high photocatalytic activity. Graphical abstract
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）