CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Shuang Yin,Dongliang Mao,Limei Pan,Xia Fang,Yang Wang,Tai Qiu,Jian Yang
The porous SiC–Si 3 N 4 composite ceramics with good EMW absorption properties were prepared by combination of gelcasting and carbothermal reduction. The pre-oxidation of Si 3 N 4 powders significantly improved the rheological properties of slurries (0.06 Pa s at 103.92 s −1 ) and also suppressed the generation of NH 3 and N 2 from Si 3 N 4 hydrolysis and reaction between Si 3 N 4 and initiator APS, thereby reducing the pore defects in green bodies and enhancing mechanical properties with a maximum value of 42.88 MPa. With the extension of oxidation time from 0 h to 10 h, the porosity and pore size of porous SiC–Si 3 N 4 composite ceramics increased from approximately 41.86% and 1.0–1.5 μm to 46.33% and ~200 μm due to the production of CO, N 2 and gaseous SiO, while the sintering shrinkage decreased from 16.24% to 10.50%. With oxidation time of 2 h, the Si 2 N 2 O fibers formed in situ by the reaction of Si 3 N 4 and amorphous SiO 2 effectively enhanced the mechanical properties , achieving the highest flexural strength of 129.37 MPa and fracture toughness of 4.25 MPa m 1/2 . Compared with monolithic Si 3 N 4 ceramics, the electrical conductivity , relative permittivity and dielectric loss were significantly improved by the in-situ introduced PyC from the pyrolysis of three-dimensional network DMAA-MBAM gel in green bodies and the SiC from the carbothermal reduction reaction between PyC and SiO 2 and Si 3 N 4 . The porous SiC–Si 3 N 4 composite ceramics prepared by the unoxidized Si 3 N 4 powders demonstrated the optimal EMW absorption properties with reflection loss of −22.35 dB at 8.37 GHz and 2 mm thickness, corresponding to the effective bandwidth of 8.20–9.29 GHz, displaying great application potential in EMW absorption fields.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 8
·49892
·
IF 2.52
Xianbo Hou,Yan Li,Xiaoguang Luo,Rubing Zhang
Polyimide (PI) aerogels enable promising application in many fields but are always inhibited by their weak resistance to high temperature and low mechanical properties. Herein, novel PI aerogel composites with efficient heat insulation and high compressive performance are prepared by introducing Silicon carbide whiskers (SiC w ) as reinforcement. The SiC w in aerogel function as shrinkage inhibitor and high temperature stabilizer. The addition of SiC w exhibits obvious enhancement and toughening effect, the compressive strength of the PI aerogel composites increases from 1.09 to 1.96 MPa. These PI aerogel composites also show enhanced high temperature stability. The as-prepared PI aerogel composites possess integrated properties of high-temperature resistance, low thermal conductivity, and high compressive strength, which can be the candidate for the application in aerospace.
✓ 已验证
产品关联
DOI
高影响因子
METALS AND MATERIALS INTERNATIONAL
·
2020
·Vol. 27
·期 10
·4263-4270
·
IF 1.99
Chen Lili,Qi Yushi,Fei Yanhan,Du Zhiming
Abstract In order to significantly enhance the performance of graphene in metal matrix composites, in situ SiC nanorods were successfully fabricated to enhance graphene nanoplatelets (GNPs)-reinforced Al2024 composite, which was prepared by powder semi-solid processing and friction stir processing. The SiC–GNPs dispersed in the Al matrix uniformly, SiC nanorods were randomly grown on GNPs sheets in any direction, bridging GNPs as well as GNPs and the Al matrix. Meanwhile, the interfacial bonding was effective. The hybrid reinforcement of SiC and GNPs endowed composites with superior mechanical properties and thermal conductivity. The in situ SiC nanorods transfer phonons and reduce phonon scattering effect in the through-plane direction of GNPs, which conducive to heat transmission. The composite exhibits improved mechanical properties, maximum tensile strength and hardness of 589 MPa and 193 HV are obtained, with 1.0 wt% GNPs addition, respectively. The thermal conductivity of composite increases with the content of SiC–GNPs. When the content of SiC–GNPs reaches 1.5 wt%, the composite has significantly enhanced thermal conductivity (224 W m −1 K −1 ), which is 115% times higher than that of Al2024. Moreover, the effects of SiC–GNPs on the properties were discussed. Graphic Abstract
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
·
2020
·
IF 7.216
Da Pang,Wei Weng,Jing Zhou,Dong Gu,Wei Xiao
Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability. We herein demonstrate a molten salt thermoelectrolysis of rice husks (RHs) mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in RHs. By coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts, the thermoelectrolysis of RHs in molten CaCl 2 –NaCl at 800 °C refines the RHs and acid-leached RHs to SiC nanowire/C (SiC-NW/C) and Si nanoparticle/C (Si-NP/C), respectively. The present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable manner.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Guanjie Zeng,Xin Li,Yanjing Wei,Tong Guo,Xiaozhong Huang,Xuelong Chen,Xiu-Zhi Tang
Porous ceramic materials with high electromagnetic absorption capacity, low density, high thermal resistance and excellent mechanical properties are highly desirable in aerospace applications. Here, we synthesized one type of hierarchical SiC composite foams with in situ grown Si 3 N 4 nanowires via a pyrolysis process. The existence and structure of Si 3 N 4 nanowires were characterized by multiple techniques and analysis revealed that the growth of nanowires was based on a typical vapor-solid mechanism. Owing to the presence of a large amount of Si 3 N 4 nanowires, both the mechanical performance and electromagnetic absorption were significantly enhanced. The minimum Reflection loss (RL) of 1.25 mm SiC composite foam reaches −50.3 dB at 16.48 GHz with an effective bandwidth (RL < −10 dB) of 3.6 GHz (14.4–18 GHz), while the toughness and specific compressive strength increased by 356% and 126%, respectively. Especially, a ductile and steady fracture behavior was observed for the mechanically enhanced composite foam, rather than the typical catastrophic failure usually seen for ceramic materials. Owing to the excellent electromagnetic wave absorption capability and enhanced mechanical properties, as well as low density and high thermal resistance, this type of composite ceramic material may find applications in aviation, aerospace and other extreme environments.
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Chuangchuang Ruan,Mengmeng Fan,Yuewen Zhang,Hongzhang Song,Xin-Jian Li,Haoshan Hao
In this work, Bi 2 Ba 2 Co 2 O y + v wt% SiC ( v = 0.00, 0.025, 0.05, 0.1, 0.2) and Bi 1.975 Na 0.025 Ba 2 Co 2 O y + w wt% SiC ( w = 0.00, 0.025, 0.05, 0.1, 0.2) ceramic samples were synthesised. The increase in the carrier concentration caused by a small amount of Na element doping leads to a decrease in the resistivity and Seebeck coefficients. The lattice distortion caused by Na element doping decrease the sample thermal conductivity . After adding SiC nanoparticles , the resistivity can be reduced further. Especially more phonons are scattered by more grain boundaries, which leads to reduced thermal conductivity. The Seebeck coefficients increase slightly due to the low energy carrier scattering effect. Considering the influence of these two factors, dispersing SiC particles on the basis of Na element doping can effectively improve the thermoelectric performance of Bi 2 Ba 2 Co 2 O y -based samples. The ZT value of the Bi 1.975 Na 0.025 Ba 2 Co 2 O y + 0.1 wt% SiC sample reaches a maximum value of 0.21 at 923 K, 26.6% higher than the Bi 1.975 Na 0.025 Ba 2 Co 2 O y sample and 93% higher than the pure Bi 2 Ba 2 Co 2 O y sample.
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 12
·1-10
·
IF 5.479
Li Xingmei,Ding Yanjun,Ling Jiang,Yao Wenyan,Zha Lagabaiyla,Li Na,Chang Yunfeng,Wang Yong,Cai Jifeng
Forensic saliva identification represents an increasingly useful auxiliary means of crime investigations, particularly in sex crimes. Salivary bacteria detection techniques have been shown to be viable methods for identifying the presence of saliva. A one-pot method is described for the fabrication of bovine serum albumin-stabilized SiC nanoparticles (SiC@BSA NPs). The SiC@BSA NPs were conjugated to antibacterial peptide GH12 to allow for fluorometric detection and imaging of bacteria in saliva. More specifically, the nanoprobe, with fluorescence excitation/emission maxima at 320/410 nm, was used to detect the oral bacteria S. salivarius levels. The detection limit is 25 cfu·mL −1 , and the assay can be performed within 40 min. The nanoprobe was also used to detect bacteria in forensic body fluids including blood, urine, and semen. In all cases, positive results were obtained with (mixed) samples containing saliva, while other saliva samples without saliva showed negative results. Fluorescent images of S. salivarius cells were obtained by implementing a high-content image analysis system. These results suggest that this new nanoprobe can be applied to screen for forensic saliva stains.
Schematic representation of the preparation of SiC@BSA-GH12 nanoprobe for fluorometric detection and imaging of S. salivarius in saliva.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2019
·
IF 4.081
Ning Guo,Ping Shen,Rui-Fen Guo,Qi-Chuan Jiang
The strength and toughness of a material are generally two mutually exclusive properties. Optimization of these properties can be realized by regulating microstructures based on a bio-inspired idea. Herein, we used gelatin as a pore-regulating agent to investigate the effect of microstructural transition from “nacre-like” lamellae to “honeycomb-like” reticulae on the mechanical properties of metal–ceramic composites. By introducing different quantities of gelatin into SiC slurries during freeze casting and infiltrating the sintered SiC scaffolds with pure molten Al, we prepared the Al/SiC (88/12 in volume) composites with variable yet controllable microstructures and further demonstrated that the desired properties could be achieved by tailoring their microstructures. Specifically, the Al/SiC composites with a fully laminated structure exhibited optimal fracture toughness ( K Jc ) of 51.9 ± 2.9 MPa m 1/2 while those with a three-dimensional reticular structure displayed peak three-point flexural strength of 371 ± 6 MPa. The relationship between the microstructures and mechanical properties of the composites was addressed based on material strengthening and toughening mechanisms.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2019
·Vol. 89
·期 3
·623-633
·
IF 1.986
An Zhimin,Ye Changshou,Zhang Rubing,Qu Qiang
Abstract A C/SiO 2 /SiC ternary aerogel was prepared from a formaldehyde–catechol/silicon source via the sol−gel method, supercritical drying, and high-temperature carbothermal reduction. The effects of different carbon/silicon molar ratios on the microstructure, chemical composition, and mechanical and shielding properties of the C/SiO 2 /SiC aerogels were investigated. The fabricated aerogels exhibited low density of 0.118–0.271 g/cm 3 , low thermal conductivity of 0.044 to 0.089 W/(m∙K) and a high specific surface area of 774 m 2 /g. The aerogel exhibited electromagnetic interference shielding effectiveness (SE) properties; the maximum SE value was 24 dB over 12.4–18.0 GHz with an absorption-dominant shielding characteristic. To improve the mechanical properties of the ternary aerogel, novel SiC w -C/SiO 2 /SiC aerogel composites were prepared by adding different contents of SiC whiskers into precursor solutions. The mechanism affecting thermal and mechanical properties of aerogel composites was investigated. This composite having high strength and low thermal conductivity had potential applications in space shuttles and reusable carrier thermal protection materials.
The fabricated C/SiO 2 /SiC ternary aerogels exhibited low density of 0.118–0.271 g/cm 3 and low thermal conductivity of 0.044−0.089 W/(m∙K). The aerogel exhibited electromagnetic interference shielding effectiveness (SE) properties; the maximum SE value was 24 dB over 12.4–18.0 GHz with an absorption-dominant shielding characteristic.
✓ 已验证
产品关联
DOI
高影响因子
Energy Technology
·
2019
·Vol. 7
·期 7
·1900017
·
IF 3.163
Zhongyi Du,Pengju Sun,Kuanhuai Wu,Xiarong Zheng,Xingfeng Zhang,Jiale Huang,Daohua Sun,Yanmei Zheng,Qingbiao Li
Graphite carbon nitride (g-C 3 N 4 ) and SiC have drawn increasing attention for application in visible light photocatalytic hydrogen evolution by water splitting due to their unique band structure and high physicochemical stability. Herein, a g-C 3 N 4 -SiC heterojunction with loaded noble metal is constructed. The g-C 3 N 4 -SiC-Pt composite photocatalysts are successfully prepared by the combination method of bio-reduction, sol deposition, and calcination. The layers of g-C 3 N 4 are thinned, and both SiC and Pt nanoparticles are simultaneously tightly bound to g-C 3 N 4 by calcination during the preparation of g-C 3 N 4 -SiC-Pt. The heterojunction formed at the interface of SiC and g-C 3 N 4 enhances the separation efficiency of the photogenerated electron–hole pairs. These composite photocatalysts achieve a high hydrogen evolution rate of 595.3 μmol h −1 g −1 with 1 wt% of deposited Pt, which is 3.7- and 2.07-fold higher than those of g-C 3 N 4 -bulk and g-C 3 N 4 -SiC under visible light irradiation with a quantum efficiency of 2.76% at 420 nm, respectively.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Wentao Xu,Youfu Zhou,He Lin,Shuai Lu,Junrong Ling,Rui Wang,Zhiguang Wang,Kun Wang
ZrC-SiC nanocomposites were synthesized via a facile, green hydrothermal precursor conversion method. The zirconium , silicon and decomposed glucose can be successfully incorporated into a homogeneous framework. In subsequent pyrolysis, the precursor transforms to a core-matrix structure of the nano-ZrO 2 and amorphous carbon/silica mixture, resulting in a short diffusion path and limited grain growth. Carbide first appears at a low temperature of 1200 °C, and the conversion is completed at 1500 °C with low oxygen content. The composite consists of grains about 100 nm, exhibiting specific embedded morphology, and has different oxidation resistance in three temperature zones based on the component. The origin mechanism and properties have been elucidated and analyzed. The present work demonstrates the effectiveness of hydrothermal chemistry for the synthesis of carbide composites and their promising application in high temperature protection. Such nanocomposites with controllable morphology and high sinterability beneficial for subsequent densification are also verified. The additive-free ceramic has been obtained with almost fully density (relative density >99%) at a low temperature of 1700 °C by spark plasma sintering (SPS). The sintered specimen possesses fine microstructure with hierarchical grain size distribution (about 1 μm and 100 nm, respectively) and good mechanical properties (fracture toughness of 4.3 ± 0.4 MPa m 1/2 and Vickers hardness of 22.8 ± 0.7 GPa).
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Jia-Qi Zheng,Jian Chen,Bu-Hao Zhang,Xue-Jian Liu,Zhong-Ming Chen,Hai-Bo Wu,Zheng-Ren Huang
SiC-MoSi 2 composites with low electrical resistivity and high infrared emissivity were fabricated via pressureless sintering. The relationship between microstructure evolution and electrical behaviors along with infrared emission properties of the resulting composites is investigated at various sintering temperatures . The electrical resistivity undergoes two significant drops with increasing sintering temperature. Pore elimination bears responsible for the initial decrease in electrical resistivity. Transmission electron microscopy (TEM) observation manifests that the thinned amorphous layers at SiC/MoSi 2 interface decrease grain boundary resistivity and allow for electrical percolation to occur when sintering temperature further rises. Additionally, increasing sintering temperature leads to a higher infrared emissivity owing to the formation of Mo 4.8 Si 3 C 0.6 and the decreased boundaries. The lowest electrical resistivity of 7.2 Ω cm and the highest infrared emissivity of 0.721 are recorded for composite sintered at 2000 ℃. Overall, SiC-MoSi 2 composites exhibit a promising prospect as infrared source elements that must endure harsh environments.
✓ 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）