CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Wenhu Hong,Shun Dong,Ping Hu,Xiaoguang Luo,Shanyi Du
Enhanced microwave absorption properties of porous PDC-SiC/Si 3 N 4 ceramics were successfully prepared through in situ growth of Si 3 N 4 nanowires (NWs) by the unidirectional freeze casting of Si 3 N 4 /camphene slurries with various polycarbosilane (PCS) contents at 1400 °C in N 2 . Si 3 N 4 NWs were in situ formed in the pore channels via a vapor-solid (VS) mechanism, the content of Si 3 N 4 NWs increased with increasing of PCS content, which tailored the microstructure and mechanical property of porous PDC-SiC/Si 3 N 4 ceramics. With the increase of PCS content, the minimum reflection coefficient (RC) of porous PDC-SiC/Si 3 N 4 ceramic decreased from −20.2 dB to −56.2 dB, and the effective absorption bandwidth (EAB) increased from 5.3 to 7 GHz, demonstrating that the porous PDC-SiC/Si 3 N 4 ceramics decorated with Si 3 N 4 NWs had a superior microwave-absorbing ability, which could be ascribed to the electronic dipole polarization and interfacial scattering enhanced by the various interfaces among Si 3 N 4 , in-situ formed PDC-SiC nanograins, nanosized carbon and Si 3 N 4 NWs phases. These findings provide significance guidance in the development of new broadband EM absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2021
·
IF 8.067
Wei Luo,Yi Liu,Chuangye Wang,Dan Zhao,Xiaoyan Yuan,Jianfeng Zhu,Lei Wang,Shouwu Guo
The morphology of MAX phase powders significantly influences their microwave absorption properties. However, the traditional synthesis via solid-state reactions produces irregular powders, and the preparation of MAX phase powders with specific morphology remains a challenge. Herein, (V 0.8 Ti 0.1 Cr 0.1 ) 2 AlC MAX phase microrods were fabricated for the first time in NaCl/KCl molten salts using vanadium, titanium, chromium, aluminum , and short carbon fibers as precursors. It was found that despite acting as a carbon source, carbon fibers also acted as sacrificial templates. By adjusting the molar ratio of metal powders and short carbon fibers, a series of carbon fiber@(V 0.8 Ti 0.1 Cr 0.1 ) 2 AlC microrods with core-sheath structure were also obtained. Carbon fiber@(V 0.8 Ti 0.1 Cr 0.1 ) 2 AlC microrods with a molar ratio of 8:2 showed the optimum microwave absorption performance. The reflection loss (RL) value reached up to –63.26 dB at 2.40 mm, and the effective absorption bandwidth (EAB) was about 5.28 GHz with a thickness of 2.02 mm. Based on the electromagnetic parameter analysis and theoretical simulation, the enhanced microwave absorption performance was attributed to the synergistic effect of different factors like dielectric loss, magnetic loss, multiple reflection, and scattering. This work offers a facile route to modulate the morphology of MAX phase powders and may accelerate its application as microwave absorbers.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Yufeng Bai,Huizhi Yang,Lili He,Chunhua Ge,Renchang Zhai,Xiangdong Zhang
As electronic device integration and power density increase, materials must have brilliant microwave absorption properties and thermal conductivity to solve electromagnetic wave pollution and thermal management problems. In this work, we attempt to construct core-shell hydroxylated boron nitride nanosheets (BN-OH) @Fe 3 O 4 @PAn (BFeA) nanocomposites by chemical synthesis and in-situ growth design. The excellent magnetic properties of Fe 3 O 4 and the good electrical conductivity of PAn can form magnetic loss and electrical loss centers to play a synergistic effect in improving microwave absorption capacity. Meanwhile, with the wave-transmitting material BN-OH as the core, the electromagnetic waves can be reflected multiple times within the absorber, which further enhances the microwave absorption capability of BFeA. As a result, the minimum reflection loss (RL min ) of the composites can reach − 49.85 dB at 11.36 GHz, and the effective microwave absorption bandwidth (RL<−10 dB, EAB) is close to 8 GHz (8.5–16.5 GHz) at a thickness of 3 mm. Simultaneously, to improve the thermal conductivity (TC) of the BFeA and reduce the interfacial thermal resistance, we use hydroxyl and dopamine as the interface linking agent at the interfaces of BN-OH and Fe 3 O 4 , and Fe 3 O 4 and PAn, respectively. In this case, the TC of BFeA-2 reaches 0.98 W (m K) −1 at a total BN–OH content of only 13 wt. %, nearly 4 times that of the raw material (Fe 3 O 4 ). This work can provide a reference for developing materials with dual functions of thermal management and microwave absorption.
研究领域:
材料科学
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电磁学
·
热传导
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Qiuyue Wang,Xiaofen Wu,Ji Huang,Siyi Chen,Yang Zhang,Chengjun Dong,Gang Chen,Lihong Wang,Hongtao Guan
With rapid advances in the portable electronics industry, the creation of microwave absorbing materials with high-performance to dissipate the unwanted electromagnetic wave is an important prerequisite. Herein, unique ternary organic-inorganic composites (C/Ni/PPy) were fabricated by hydrothermal method combined with in-situ polymerization approach. The correlation between structure, components, and microwave absorption capability is investigated in detail. The carbon matrix was prepared through a typical “carbonization-activation” procedure. Then, the PPy particles were decorated on the surface of the biomass carbon matrix incorporated with Ni particulates via an in-situ polymerization method. The microwave absorbing results suggest that the C/Ni/PPy ternary composites exhibit stronger dielectric loss and microwave absorption capabilities than C/PPy binary composites. A reflection loss of − 42.09 dB and an outstanding effective absorption bandwidth of 5.24 GHz are achieved simultaneously with a thickness of only 2.4 mm. The excellent microwave absorbing performances can be ascribed to the unique microstructure, enhanced polarization and the synergistic effects between dielectric loss and magnetic loss. The present work achieves a new paradigm to improve microwave absorption characteristics through the combination of dielectric components with magnetic materials. Furthermore, a prototype is proposed, which has broad application prospects for applications in next-generation wearable and portable electronics.
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
International Journal of Minerals Metallurgy and Materials
·
2023
·Vol. 30
·期 3
·548-558
·
IF 4.8
Li Qiuying,Lu Yiheng,Shao Zhuoyan
A new type of composite filler was designed by a modified sol—gel method using fly ash (FA), Fe(NO 3 ) 3 ·9H 2 O, and Ni(NO 3 ) 2 ·6H 2 O as raw materials. The composite filler was a spherical core-shell structure composed of FA as the core and NiFe 2 O 4 as the shell. Further, the composite filler was added into the silicone rubber to fabricate the high temperature vulcanized microwave absorption materials; X-ray diffraction, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscope confirmed that NiFe 2 O 4 was successfully coated on the surface of FA and formed a uniform and continuous coating layer. As expected, silicone rubber filled with the composite filler had a minimum reflection loss of −23.8 dB at 17.5 GHz with the thickness of 1.8 mm, while the effective absorption bandwidth was as high as 12 GHz. The addition of the composite filler greatly enhanced the microwave absorption properties of the system, which was resulted from multiple losses mechanism: interface polarization losses, magnetic losses, and multiple reflection losses. Also, silicone rubber filled with the composite filler exhibited excellent thermal stability, flexibility, environmental resistance, and hydrophobicity compared with traditional silicone rubber. Therefore, this work not only responds to the green chemistry to achieve efficient FA recovery, but also devises a new strategy to prepare microwave absorption materials with strong potential for civilian applications.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Huying Yan,Yang Guo,Xingzhi Bai,Jiawei Qi,Xiangyu Zhao,Haipeng Lu,Longjiang Deng
Developing a lightweight microwave absorbing materials (MAMs) with high absorption capacity at low thickness is a perennial challenge in materials engineering. Herein, a light Ti 3 C 2 T x @Carbon/NiZn ferrite (Ti 3 C 2 T x @C/NZFO) composite is designed by synergistically incorporating dielectric–magnetic components. The inclusion of C and NZFO enhances the interfacial polarization of the substrate and optimizes its impedance matching. Additionally, the presence of NZFO also produces magnetic loss mechanisms, such as natural and exchange resonance, as well as eddy current loss. Spontaneously, Ti 3 C 2 T x @C/NZFO composite achieved a minimum reflection loss ( RL ) of –44.7 dB at 12.5 GHz and displayed an effective absorption bandwidth of 4.27 GHz (13.53–17.8 GHz) at a thin thickness of 1.3 mm ( RL < –10 dB). Besides, the Ti 3 C 2 T x @C/NZFO composite exhibits the smallest radar cross–section (RCS) value, which further corroborates its outstanding microwave absorption performance. This research offers a groundbreaking approach to designing lightweight and thin MAMs.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lingyu Jia,Tingting Yang,Zixu Chen,Xingqi Liao,Peigang He,Dechang Jia,Xiaoming Duan,Zhihua Yang,Yu Zhou
In this work, we utilized an in-situ chemical synthesis method to fabricate a Fe 3 O 4 /K-geopolymer (KGP) composite to be applied in a microwave absorbent field. This material, as a type of ceramic precursor, is highly expected to be a 3D printing material to prepare microwave absorbing components with complex shapes. The investigation results demonstrate that the material possesses a large effective microwave absorbing bandwidth of 3.7 GHz with the minimum reflection loss reducing to −12.2 dB when the generated Fe 3 O 4 percent reaches 12 wt% in the KGP composite. This microwave absorbent performance can be attributed to a synergistic effect between the eddy current loss caused by the improved electrical conductivity of magnetic nanoparticles and the interfacial polarization effect from the geopolymer matrix and magnetic medium interface. Also, we used direct ink writing technology to print two-dimensional components with desirable patterns. Thickness-dependent wave absorption evaluation results confirmed a maximum reflection loss of −25.9 dB at 15.2 Hz was obtained from the printed sample containing 9.0 wt% Fe 3 O 4 for a layer thickness of 10 mm, indicating that wave consumption effectiveness was determined by porous microstructures, magnetic loss of Fe 3 O 4 nanoparticles as well as suitable impedance matching. The preparation method and synthesized material pave the way for integrated manufacturing of 3D printing components with microwave absorbing performance.
研究领域:
材料科学
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电磁学
·
制造工程
✓ 已验证
DOI
高影响因子
CARBON
·
2025
·
IF 11.6
Lin Xie,Ruilin Liu,Xiaomeng Jiang,Cui Ni,Baolei Wang,Chuanxin Hou,Di Lan,Wei Du,Xiubo Xie
In order to obtain multiple interfaces of Co/CoO by tuning the oxidation process and simultaneously clarify the interface migration, Co particles loaded on mangosteen shell-derived carbon (MSC) were prepared, and then oxidized under a mixed atmosphere of Ar/O 2 and 300 °C with different oxidation time. Due to the existence of MSC, the Co can completely oxidized in short time of 60 min and low O 2 concentration of 5 %. The oxidation process is: Co→CoO→Co 3 O 4 . A lot of defects in-situ formed in the oxidation process can be clearly detectable. Co/MSC composites oxidized at 300 °C for 10 min exhibits considerable minimum reflection loss of −37.86 dB and an effective absorption bandwidth of 5.28 GHz among the composites with different oxidation times. The Co/CoO, CoO/C, Co/C heterogeneous interfaces are conducive to the depletion of electromagnetic waves through interfacial polarization. The in-situ formed defects are positive for enhancing the dipole prolarization, and the natural resonance is also enhanced due to the presence of Co and its oxides. The positive effects of carbon additive in the oxidation of Co on the in-situ defects formation and multiple interface construction provide a new perspective for designing high performance microwave absorption materials.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 2
·1-13
·
IF 2.8
Hua Wanlu,Hu Chunyan,Xie Xiaoli,Gou Guangjun
The three-dimensional (3D) porous carbon materials are helpful for forming thin, light-weight, wide effective absorption bandwidth and strong absorption intensity absorbers. However, previous methods were not environmentally friendly enough. Thus, in this work, the Fe/Fe 3 C@porous carbon was synthesized from soluble starch and Fe(NO 3 ) 3 ·9H 2 O via chemical bowling and subsequent carbonization at 700 °C with different ratios. When the ratio of starch to Fe(NO 3 ) 3 ·9H 2 O is 1:1.5, the porous carbon exhibits a strong absorption ability with minimum reflection loss ( RL min ) value of −16.64 dB at 16.78 GHz, when the thickness is 1.75 mm and the proportion of paraffin wax is 30 wt%. The synergy of well impedance matching, sufficient loss performance, and interface polarization makes 3D porous carbon materials an excellent wave absorber. This work provides a good inspiration for studying outstanding performance microwave absorption materials.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Yanlong Sun,Tong Zheng,Guangshan Zhang,Bei Liu,Peng Wang,Afed Ullah Khan
ABSTRACT This work focuses on the synthesis of microwave absorbing-catalytic multifunction novel adsorbent. During adsorbent design secondary pollution produced by adsorbent regeneration is continuously neglected, which motivates the author to load catalyst on adsorbent to enhance the mineralization of adsorbed organic compounds during thermal regeneration. Microwave absorption fuels the synthesis and regeneration of adsorbent. The morphology and structure of composite adsorbent are analyzed by X-ray diffraction, scanning electron microscope-energy dispersive spectrometer, transmission electron microscope, and Brunauer–Emmett–Teller-Barrett–Joyner–Halenda method. The results show that the synthesized composite adsorbent is mesoporous with wide pore diameter distribution and 252 m 2 /g specific surface area. The host of composite adsorbent is γ-Al 2 O 3 and the loaded catalyst is amorphous manganese oxides. The synthesis process of composite adsorbent is designed and evaluated by the response surface methodology using a Box–Behnken design method. After optimization, the optimal adsorption capacity of composite adsorbent can reach up to 135 mg/g, and more than 47% tetracycline can be mineralized into H 2 O and CO 2 during 5 min regeneration. The properties of the composite material can be changed by adjusting synthesis condition. These designed functions of material will make adsorbent more adaptable to meet the growing demand of the environmental standard.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Mingxu Sui,Tianqi Fu,Xiaodong Sun,Guangzhen Cui,Xuliang Lv,Guangxin Gu
Unary and binary M 2+ (M=Mn, Co, Ni, Zn) substituted hollow Fe 3 O 4 were prepared by one-step solvothermal method. The crystallographic structure, morphology, element components and microwave absorbing properties of as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), Energy-dispersive X-ray (EDX) and vector network analyzer (VNA). The unary and binary Co 2+ substitution of hollow Fe 3 O 4 could result in a significant improvement of microwave absorption performance, including the expanding of effective absorption bandwidth, the thinner thickness and the increment of absorbing intensity. The sample of CoFe 2 O 4 could reach an optimal reflection loss of − 28.78 dB at 15.52 GHz under the thickness of 1.5 mm, moreover, the efficient absorption bandwidth (less than −10 dB) is expanded to 5.56 GHz which is most outstanding among these samples. The minimum reflection loss of Co 0.75 Zn 0.25 Fe 2 O 4 could reach − 49.60 dB at 9.88 GHz under the thickness of 2 mm. The as-prepared products could be used as microwave absorber with the advantages of strong absorption, broad bandwidth and thin thickness. The favorable performance could be attributed to the strong magnetic loss, dielectric loss and good impedance matching properties.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 20
·3699
·
IF 5.719
Congyi Qian,Xiaohui Liang,Mei Wu,Xingxin Zhang
A lightweight microwave-absorbing material with a strong electromagnetic-absorption capability of practical significance in the field of electromagnetic compatibility was obtained by adjusting the ratio of Fe3O4and rGO. A nanoparticle material with a chain-typed structure consisting of a combination of Fe3O4and rGO was produced by a hydrothermal method under an applied magnetic field. The electromagnetic loss property of the Fe3O4@rGO composites is studied in the frequency range from 2 to 18 GHz. In addition, the reflection loss and the mechanism of microwave absorption are explored. By changing the amounts of rGO, the electromagnetic loss of the Fe3O4@rGO composites can be effectively regulated, which obtain better reflection loss. The minimum reflection loss of the Fe3O4@rGO composites is −49.4 dB at 16.2 GHz only with a thickness of 1.75 mm. Thus, the Fe3O4@rGO composites have an extremely thin thickness and a strong electromagnetic wave absorption capacity, which is a candidate for the development of lightweight magnetic absorbing materials.Keywords:magnetic composites;microwave absorption;electromagnetic loss;lightweight
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）