MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Panpan Xu,Yupeng Wang,Wentao Hao,Li Sun,Ensi Cao,Yongjia Zhang
(In 0.5 Nb 0.5 ) x Ti 1-x O 12 (INTO) ceramics exhibit the unusual dielectric properties of giant dielectric constant and good stabilities, but their low-frequency dielectric loss is relatively large, and the sintering temperature is too high, which are very disadvantageous for practical applications. According to internal barrier layer capacitance effect, which seems to be the most plausible mechanism of the unusual dielectric properties , constructing insulating phase boundaries in INTO ceramics is an effective way to reduce their low-frequency dielectric loss. In this paper, SiO 2 was added to INTO ceramics, because, on the one hand, the insulating phase boundaries could be constructed by SiO 2 , on the other hand, SiO 2 could play the role of sintering agent to reduce the sintering temperature. Therefore, the SiO 2 /INTO ceramics were prepared by solid-state reaction, and their crystalline structures, microstructures, and electrical properties were analyzed. Compared to previous reports, the low-frequency dielectric loss of SiO 2 /INTO ceramics after annealing, which were sintered at a lower temperature of 1300 °C for a shorter time of 5 h, decreases substantially. The reason was discussed.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2025
·
IF 3.5
Wang Zhan,Jinhong Mo,Lingling Tang,Fan Shi,Le Chen,Lixia Li,Mingyi Chen,Qinghong Kong,Ru Zhou,Juncheng Jiang
Considering that the poor mechanical properties limit the application of SiO 2 aerogels in fire insulation, polyurethane sponges, and mica were used to enhance the mechanical properties of SiO 2 aerogels in this study. The effects of polyurethane sponges with different pore sizes and mica content on the thermal-mechanical properties of composite aerogels were investigated. The internal structure of the composite aerogels was analyzed by scanning electron microscopy. Moreover, the chemical structure and composition of the composite aerogels were characterized and analyzed. The results demonstrate that polyurethane sponges and mica can effectively enhance the mechanical properties of composite aerogels. However, the addition of mica increased the thermal conductivity. The experimental data will further expand the engineering application of SiO 2 aerogels.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Huanhuan Niu,Xueyang Tu,Shuang Zhang,Yaya Li,Hailong Wang,Gang Shao,Rui Zhang,Hongxia Li,Biao Zhao,Bingbing Fan
Ti 3 C 2 T x nanosheets are attractive for electromagnetic wave absorption (EMA) materials requiring ultra-thin and high-performance due to their high conductivity and polarizability. However, the self-restacking of Ti 3 C 2 T x nanosheets unavoidably decreases the number of active sites, specific surface area, and conductivity. Herein, a simple strategy is developed to prepare a core–shell structure of SiO 2 @Ti 3 C 2 T x by electrostatic assembly and hydrogen bonding. SiO 2 spheres as templates cannot only prevent Ti 3 C 2 T x nanosheets from further stacking, but also modulate the surface impedance and significantly increase interfacial polarization loss. The resulted SiO 2 @Ti 3 C 2 T x composite can deliver superior absorption capacity with minimum reflection coefficient (RL) of −58.01 dB at an ultra-thin thickness of only 1.3 mm. The absorption efficiency is calculated over 99.999 % with an effective absorption bandwidth (EAB) of 3.44 GHz. Furthermore, with increasing amounts of SiO 2 templates, the EAB can be broadened up to 15.04 GHz (2.96–18 GHz) in the thickness range of 1–3 mm. The absorption mechanisms are described based on multiple reflection, polarization behaviors, tunable impedance matching, and conduction loss. The present work could pave a way for obtaining ultra-thin, high-performance MXene-based EMA materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
Journal of Coatings Technology and Research
·
2024
·Vol. 21
·期 4
·1499-1512
·
IF 2.3
He Jianjun,Yan Jingyi,Pu Min,Jie Jun,Luo Guangwu,Zeng Zijing,Duan Zihao,Huang Caiyuan
Ice on the surface of wind turbine blades may result in power production losses and unsafe operations. An effective technological solution to the ice issue is coating de-icing. This study first constructed SiO 2 aerogel/CNTs (carbon nanotube) coating with photothermal de-icing by incorporating photothermal nanoparticles into the created nanoporous structure. The coating structure examined by SEM and EDS analysis demonstrates that CNT particles can be well captured by the three-dimensional nanostructure of SiO 2 aerogel and form a stable symbiotic skeleton. After that, we examined how the quantity of CNT doping affected the coating's surface morphology and photothermal properties. The findings demonstrated that the C-6 coating made from 0.6% CNTs performed best. Utilizing the photothermal effect of CNTs, it exhibited a steady rate of temperature increase and reached the target temperature of 153.4°C in 561 s upon near-infrared light (808 nm) irradiation. According to the results of experiments testing the photothermal performance, mechanical/chemical stability, and applicability of the coating, the coating has the advantages of being lightweight, provides quick de-icing, high stability, and simple production. This study not only increases the viability of using coating de-icing technology on wind turbine blades but also offers creative solutions to scientific investigation in the area of coating de-icing.
研究领域:
材料科学
·
能源工程
·
环境科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2018
·
IF 2.829
Zhou Zhou,Hao Wang,Zhicai Zhu,Hui Yang,Qilong Zhang
This paper reports a feasible method to prepare polymeric nanocomposites with enhanced dielectric, electromechanical and hydrophobic performance by introducing the core-shell AgNWs@SiO 2 filler into polydimethylsiloxane (PDMS). The homogenous core-shell AgNWs@SiO 2 was firstly synthesized through a two-step sol-gel process. The thicknesses of AgNWs and SiO 2 coating layer are approximately 70 nm and 20 nm, respectively. The dielectric constant is improved effectively due to enhanced interfacial polarization, while extremely low dielectric loss and conductivity are achieved by introducing the insulating SiO 2 interlayer to moderate the internal surface area of core-shell nanowires and restrict the electron transfer between Ag nanowires. Typically, the PDMS nanocomposites with 20 wt% AgNWs@SiO 2 have a dielectric constant of 6.7, nearly 2.7 times larger than that of pure PDMS, and remains a quite low loss of 0.02 at 1 kHz. Meanwhile, nanocomposites also show improved electromechanical and hydrophoic properties. Nanocomposites with 10 wt% AgNWs@SiO 2 exhibit the highest electromechanical sensitivity ( β= 9.04), about 12.6 times higher than that of pure PDMS at 1 kHz. The static contact angle of nanocomposties with 20 wt% AgNWs@SiO 2 reaches 129°. All the improved performances show great potential application for dielectric elastomer material and electrowetting devices.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2018
·Vol. 124
·期 3
·1-10
·
IF 1.604
Liu Min,Kang Ming,Chen Kexu,Mou Yongren,Sun Rong
Integrating the processes of preparation of CaCO 3 :Eu 3+ and its surface-coating, core–shell structured CaCO 3 :Eu 3+ @SiO 2 phosphors with red emission were synthesized by the carbonation method and surface precipitation procedure using sodium silicate as silica source. The phase structure, thermal stability, morphology and luminescent property of the as-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectrum, thermal analysis, field-emission scanning electron microscopy, transmission electron microscope and photoluminescence spectra. The experimental results show that Eu 3+ ions as the luminescence center are divided into two types: one is at the surface of the CaCO 3 and the other inhabits the site of Ca 2+ . For CaCO 3 :Eu 3+ @SiO 2 phosphors, the SiO 2 layers are continuously coated on the surface of CaCO 3 :Eu 3+ and show a typical core–shell structure. After coated with SiO 2 layer, the luminous intensity and the compatibility with the rubber matrix increase greatly. Additionally, the luminous intensity increases with the increasing of Eu 3+ ions concentration in CaCO 3 core and concentration quenching occurs when Eu 3+ ions concentration exceeds 7.0 mol%, while it is 5.0 mol% for CaCO 3 :Eu 3+ phosphors. Therefore, preparation of CaCO 3 :Eu 3+ @SiO 2 phosphors can not only simplify the experimental process through integrating the preparation of CaCO 3 :Eu 3+ and SiO 2 layer, but also effectively increase the luminous intensities of CaCO 3 :Eu 3+ phosphors. The as-obtained phosphors may have potential applications in the fields of optical materials and functional polymer composite materials, such as plastics and rubbers.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 2
·255
·
IF 3.164
Tao Xu,Qiangqiang Xiao,Jiayu Chen,Li Li,Xiongjun Yang,Lifang Liu,Wenhui Yuan,Bingjian Zhang,Huijun Wu
This study proposes to utilize modified Nano-SiO2/fluorinated polyacrylate emulsion that was synthesized with a semi-continuous starved seed emulsion polymerization to improve the hydrophobicity, thermal stability, and UV-Vis absorption of polyacrylate emulsion film. To verify the proposed method, a series inspection had been conducted to investigate the features of the emulsion film. The morphological analysis indicated that Nano-SiO2was surrounded by a silane molecule after modification, which can efficiently prevent silica nanoparticles from aggregating. Fourier transform infrared spectra confirmed that modified SiO2and dodecafluoroheptyl methacrylate (DFMA) were successfully introduced to the copolymer latex. The particle size of latex increased with the introduction of modified Nano-SiO2and DFMA. UV-Vis absorption spectra revealed that modified silicon nanoparticles can improve the ultraviolet shielding effect obviously. X-ray photoelectron spectroscopy illustrated that the film–air interface was richer in fluorine than film section and the glass side. The contact angle of modified Nano-SiO2/fluorinated polyacrylate emulsion containing 3 wt % DFMA was 112°, slightly lower than double that of polyacrylate emulsion, indicating composite emulsion films possess better hydrophobicity. These results suggest that introducing modified Nano-SiO2and fluorine into polyacrylate emulsion can significantly enhance the thermal stability of emulsion films.Keywords:polyacrylate emulsion;nano-SiO2;fluorine;ultraviolet shielding effect;hydrophobicity
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2017
·
IF 5.099
Junxing Huang,Chuanzhou Liang,Xu Zhang
The application of nanotechnology in agriculture, pesticide delivery and other related fields increases the occurrence of engineered nanoparticles (ENPs) in soil. Since ENPs have larger surface areas and normally a high adsorption capacity for organic pollutants, they are thought to influence the transport of pesticides in soils and thereafter influence the uptake and transformation of pesticides. The adsorption pattern of racemic-metalaxyl on agricultural soils including kinetics and isotherms changed in the presence of nano-SiO 2 . The adsorption of racemic-metalaxyl on agricultural soil was not enantioselective, in either the presence or the absence of SiO 2 . The adsorption of racemic-metalaxyl on SiO 2 decreased to some extent in soil-SiO 2 mixture, and the absolute decrease was dependent on soil properties. The decreased adsorption of metalaxyl on SiO 2 in soil-SiO 2 mixture arose from the competitive adsorption of soil-dissolved organic matter and the different dispersion and aggregation behaviors of SiO 2 in the presence of soil. Interactions between SiO 2 and soil particles also contributed to the decreased adsorption of metalaxyl on SiO 2 , and the interactions were analyzed by extended Derjaguin–Landau–Verwey–Overbeek theory. The results showed that the presence of nano-particles in soils could decrease the mobility of pesticides in soils and that this effect varied with different soil compositions.
研究领域:
环境科学
·
土壤学
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Wenzhi Li,Lihong Gao,Yanbo Liu,Zhuang Ma,Fuchi Wang,Hezhang Li
During the fabrication of functional high-endothermic-enthalpy graphite/SiO 2 composite coating , the oxidation and vaporization of raw materials have become serious issues in hyperthermal preparation environment. In this study, these issues were addressed through densification and modification of the feedstock powder. Then, the corresponding coating was prepared by optimized plasma-spraying parameters. By investigating the modified feedstock powder and the resulting splats and coatings by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy, we realized an optimized composite feedstock powder preparation process and an ideal coating structure. The compactness of the powder reached its optimum after treating at 1400 °C for 2 h. After heat treatment densification and Ni shell covering processes, the modified powder exhibited good oxidation resistance , vaporization resistance, and spreading performance during plasma spraying . Thus, a pure and dense composite coating was prepared. Positive laser resistance performance was observed during the initial laser ablation test, which proved that this modified graphite/SiO 2 coating has good application potential in the laser protection field. Moreover, this study provides an experimental basis and a feasible method for difficult-to-spray composite coatings’ preparation, such as graphite/SiO 2 composite.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
Chemical Science
·
2022
·Vol. 13
·期 16
·4616-4622
·
IF 9.969
Jianxin Zhai,Baowen Zhou,Haihong Wu,Shuaiqiang Jia,Mengen Chu,Shitao Han,Wei Xia,Mingyuan He,Buxing Han
Design of active catalysts for chemical utilization of methane under mild conditions is of great importance, but remains a challenging task. Here, we prepared a Ag/AgCl with SiO2 coating (Ag/AgCl@SiO2) photocatalyst for methane oxidation to carbon monoxide. High carbon monoxide production (2.3 μmol h−1) and high selectivity (73%) were achieved. SiO2 plays a key role in the superior performance by increasing the lifetime of the photogenerated charge carriers. Based on a set of semi in situ infrared spectroscopy, electron paramagnetic resonance, and electronic property characterization studies, it is revealed that CH4 is effectively and selectively oxidized to CO by the in situ formation of singlet 1O2via the key intermediate of COOH*. Further study showed that the Ag/AgCl@SiO2 catalyst could also drive valuable conversion using real sunlight under ambient conditions. As far we know, this is the first work on the application of SiO2 modified Ag/AgCl in the methane oxidation reaction.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2023
·Vol. 13
·期 8
·1261
·
IF 2.7
Zhen Pei,Haixiao Huang,Xingzhong Guo,Jinming Zhang,Mingxing Chen
MgO–Al2O3–SiO2(MAS) glass–ceramics with controllable crystalline phases were successfully prepared using the melting method followed by heat treatment. The effects of the main components of glass on the crystallisation kinetics, nucleation, crystallisation and properties of glass–ceramics were investigated in detail. As the Al2O3and MgO contents increase and SiO2content decreases, the crystallisation peak temperature and activation energy of MAS glass decrease, while the crystal growth tends to follow a homogeneous nucleation crystallisation. The MAS glass nucleation temperature and time increase with higher concentrations of Al2O3and MgO and with a lower SiO2concentration. Mg2(Al4Si5O18) indialite and MgAl2O4spinel precipitate simultaneously in the MAS glass after crystallisation; the relative proportion of crystalline phases is related to the composition and crystallisation temperature. A higher SiO2content allows the formation of a dominant indialite phase, while higher MgO and Al2O3contents promote the formation of a dominant spinel phase. The MAS glass ceramic with a greater indialite phase has good dielectric properties with a dielectric constant of 6.499 and dielectric loss of 0.0064, while that of a higher spinel phase possesses improved mechanical properties, with a Vickers hardness of 715 Hv and a bending strength of 244.9 MPa.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Wei Liu,Jiale Song,Hui Zhao,Zhaokuan Cui,Shuheng Zhang,Yu Qiao,Chenhong Cao,Weiguang Li
The superhydrophobic coating can effectively inhibit the intrusion and adhesion of water-corrosive media on the surface of concrete. However, the poor mechanical stability and expensive materials significantly restricts its application in concrete engineering. Thus, superhydrophobic nano-SiO 2 @silane/silicate coating are successfully prepared by simply spraying nano-SiO 2 @silane on the surface of mortar pretreated by silicate. The pretreated silicate can enable the surface of mortar to enhance flatness and compactness, offering an optimal substrate for spraying nano-SiO 2 @silane hydrolysate. Further, the low surface energy of silane and the micro-nanostructure formed by nano-SiO 2 synergistically make the composite coating possess excellent superhydrophobic properties, with a contact angle of 154° and a slide angle of 5°. Notably, compared with original mortar, the water absorption rate, water vapor transmission rate, and chloride ion penetration depth are reduced by 86.4 %, 67.3 % and 87.9 %, respectively, exhibiting outstanding impermeability. In addition, the coated mortar possesses excellent self-cleaning properties and resistance to rain erosion. Meanwhile, the coated mortar also exhibits excellent resistance to mechanical wear (>200 cycles of abrasions) and resistance to UV radiation (>100 h). Such outstanding comprehensive performance can guarantee concrete to long-term apply in outdoors. This work provides a simple, feasible, economical, and effective research idea for developing superhydrophobic coatings on concrete.
研究领域:
建筑材料学
·
表面工程学
✓ 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）