CORROSION SCIENCE
·
2024
·
IF 7.4
Yueqi Wu,Mingyong Jia,Zhifeng Huang,Qiang Shen,Fei Chen
The high-temperature corrosion behavior of a Si 3 N 4 /W composite under the molten MgCl 2 -NaCl-KCl salts has been investigated. It is suggested that the molten salts diffuse along the physical surface defects and enter the interior of adjacent Si 3 N 4 /W grains, leading to the 9.1% bending strength loss after 400 hours for corrosion. In air atmosphere, oxidation products WO 2 , WO 3 , and corrosion product MgWO 4 caused a 34.3% bending strength decrease after 400 hours for corrosion. This study elucidates the high-temperature molten chloride salt corrosion mechanisms of the Si 3 N 4 /W composite material under two different atmospheres. The composite demonstrates relatively excellent corrosion resistance in service environments.
研究领域:
材料科学
·
腐蚀工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS
·
2024
·
IF 1.2
Xiaoli Ji,Zhihao Xu,Jian Liu,Ruochen Qiao,Haoze Yuan
MWCNT/Fe3O4/Si3N4 composite was synthesized via hydrothermal synthesis. The morphology and structure of MWCNT/Fe3O4/Si3N4 were investigated by means of SEM, XPS, XRD, and FT-IR. Their electromagnetic parameters were measured by a vector network analyzer. The microwave attenuation properties of as-synthesized composite could be modulated by regulating the feed ratio of MWCNT, Fe3O4, and Si3N4. According to the different amounts of modified nano Fe3O4 added, they are labelled as S1-S3. When the feed ratio is 3:15:20, the maximum reflection loss value of the sample is −23.3 dB at 14.4 GHz, the corresponding thickness is 2.5 mm, and the corresponding effective absorption bandwidth is 5.36 GHz. Moreover, the test results of the thermogravimetric analyzer show that the composite material has excellent heat resistance. Our research results provide a reference value for the development of excellent heat resistance and high-performance MWCNT-based microwave absorption composite 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
COMPOSITES COMMUNICATIONS
·
2025
·
IF 7.7
Qinghe Shi,Kang Jin,Yuxuan Zhang,Hongyan Xia
Fiber-reinforced resin matrix composites are widely used in organic printed circuit boards (PCBs). However, conventional glass fiber reinforced epoxy resin (EP) matrix composites suffer from low thermal conductivity and poor electrical properties. Herein, to coordinate the thermal and electrical properties of the composites, a novel c-BN/EP/Si 3 N 4 composite for PCBs was prepared by hot-pressing moulding method by selecting Si 3 N 4 fibers instead of glass fibers and introducing nano cubic boron nitride (c-BN) particles as filler at the same time. Combined with Si 3 N 4 fibers, nano c-BN filler with suitable content can further improve thermal transfer capacity and limit the volume shrinkage of EP during curing, resulting in the decreased porosity and strong interfacial bonding between Si 3 N 4 fibers and EP. When c-BN content is 20 wt%, the c-BN/EP/Si 3 N 4 composite shows excellent in-plane thermal conductivity (2.124 W m −1 K −1 ), low coefficient of thermal expansion (4.34 ppm K −1 ) and excellent breakdown strength (55.71 kV mm −1 ). Therefore, the c-BN/EP/Si 3 N 4 composites have a potential application in the field of organic PCBs substrates.
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
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yeye Liu,Leilei Zhang,Fei Zhao,Chang Li,Hongchao Sheng,Hejun Li
Paper with simultaneous fire-resistance and hydrophobicity have greatly potential applications in the fields of packing, storage and delivering information, which attracts increasing attention recently. Different from the traditional cellulose-based paper which is extremely easily damaged by water and fire, a new type of highly flexible, fire-resistant and hydrophobic paper based on Si 3 N 4 nanowires and polydimethylsiloxane (PDMS) is reported. Specially, the Si 3 N 4 @PDMS core-shell nanowires with 3D interlocking structure are designed, in which the Si 3 N 4 nanowires act as the inorganic fire-resistant frameworks and the PDMS shell with low surface energy provides the hydrophobic surface . The Si 3 N 4 @PDMS core-shell nanowires are intertwined and interlaced to form a highly flexible Si 3 N 4 @PDMS paper. The tensile strength of Si 3 N 4 @PDMS paper is 6.19 MPa, indicating the good mechanical property. The obtained Si 3 N 4 @PDMS paper has the characteristics of writability, fire-resistance and hydrophobicity. The high thermal stability of Si 3 N 4 nanowires makes Si 3 N 4 @PDMS paper exhibit excellent fire resistance. No obvious change is observed for the commercial paper with Si 3 N 4 @PDMS paper as the fire-shielding layer after heating for 30 min. In addition, the contact angles of water droplets are all greater than 110° over the surfaces of Si 3 N 4 @PDMS paper after mechanical damages, chemical corrosions and thermal treatments. Si 3 N 4 @PDMS paper can be used in oil/water separation and oil collection. More importantly, Si 3 N 4 @PDMS paper can be used for writing without being damaged by fire or water. The present work may inspire the development and application of functional paper and is expected to become a breakthrough in the traditional paper industry.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
The effect of the GdH 2 on the shrinkage behavior, microstructure, thermal conductivity , and flexural strength was investigated. The pre-sintering enables the elimination of native SiO 2 and the simultaneous formation of Gd 2 O 3 . The N/O ratio in the liquid phase was increased because of the increasing Gd 2 O 3 /SiO 2 ratio, resulting in the restricted shrinkage during gas pressure sintering. The high N/O ratio in the liquid phase benefits not only the nucleation and growth of β-Si 3 N 4 but also the removal of lattice oxygen, leading to the increase of thermal conductivity . Although the replacement of Gd 2 O 3 by GdH 2 leads to enhanced flexural strength at low temperature, it tends to reduce the flexural strength at high temperature. This variation related largely to the exaggerated bimodal microstructure. This work signifies that GdH 2 is an effective sintering additive for obtaining Si 3 N 4 ceramics with both high flexural strength and high thermal conductivity.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Qingxuan Zhou,Yang Wang,Zhuoqun Han,Jia Liu,Jie Zhao,Wei Chu,Zhicheng Zhao,Jian Li,Zhiqiang Cheng,Ling Li,Futian Liu
Due to the low powder content characteristic of digital light processing in the preparation of ceramic green bodies, significant challenges arise in obtaining high-density, high-performance Si 3 N 4 ceramic. Sintering aids exert a critical influence on the densification and properties of Si 3 N 4 ceramics. To further improve the performance of 3D-printed Si 3 N 4 ceramics, Si 3 N 4 ceramics were fabricated using DLP technology combined with gas pressure sintering employing different ratios of La 2 O 3 -MgO as sintering aids. The ceramic slurries, microstructures, and ceramic performance were studied systematically. The results showed that increasing the proportion of· La 2 O 3 powder enhanced the rheological and curing properties of Si 3 N 4 ceramic slurries. Varying the La 2 O 3 -MgO ratio affected the composition of the liquid phase, leading to differences in the densification and grain growth of Si 3 N 4 ceramics. The average grain size increased with higher ratios of La 2 O 3 -MgO, and reached a maximum value of 0.91 μm with a ratio of 9:1. With the increase of the La 2 O 3 -MgO ratio, the bulk density and shrinkage rate of the ceramics initially increased and then declined. In addition, the flexural strength and fracture toughness of the ceramics peaked at a ratio of 3:7 for La 2 O 3 -MgO, measuring 577 ± 16.28 MPa and 5.84 ± 0.17 MPa m 1/2 , respectively. These results demonstrate that high-performance Si 3 N 4 ceramics can be effectively prepared using DLP technology by adapting the ratio of sintering additives.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 101
·期 11
·4870-4875
·
IF 2.956
Wei-Ming Guo,Li-Xiang Wu,Jun-Jie Yu,Ling-Yong Zeng,Shi-Kuan Sun,Jing-Xi Li,Shang-Hua Wu,Hua-Tay Lin,Cheng-Yong Wang
Based on the previous work on Si 3 N 4 –ZrB 2 [Wu et al. J Eur Ceram Soc ;2017,37:4217], the influence of ZrB 2 addition on the phase and microstructure evolution of Si 3 N 4 –ZrB 2 composites was emphatically investigated, and the mechanical properties were compared with pure Si 3 N 4 ceramics. It was revealed that the ratio of β- to (α+β)-Si 3 N 4 significantly increased from 14.3% in pure Si 3 N 4 ceramics to 39.8% in Si 3 N 4 with 15 vol% ZrB 2 addition, indicating that the introduction of ZrB 2 promoted α- to β-Si 3 N 4 phase transformation. As a consequence, the microstructure of the composite showed the bimodal distribution, containing both elongated and equiaxed Si 3 N 4 grains. For the pure Si 3 N 4 , Vickers hardness, fracture toughness and flexural strength was 22.8 GPa, 7.6 MPa m 1/2 , and 334.5 MPa, respectively. In contrast, the composite of Si 3 N 4 –30 vol% ZrB 2 simultaneously possessed an excellent combination of mechanical properties: 19.5 GPa in hardness, 9.8 MPa m 1/2 in toughness and 702.0 MPa in strength. Present study suggested that Si 3 N 4 -based ceramics with high hardness, high toughness, and high strength could be obtained by the combination of appropriate ZrB 2 content and low hot-pressing temperature.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2024
·
IF 6.1
Qiang Liu,Jiarui Yang,Guoqing Tian,Zhenhui Huang,Liying Shen,Chuyan Hu,Baihan Wang,Kaiyang Wang,Shuang Feng,Feng Ye
Materials with high specific strength and toughness are urgently needed in the fields of electronic packaging, armor, and aerospace. SiC/Al composites show good potential for these applications but the problem of mutual exclusion of strength and toughness still needs to be solved. Herein, we propose a new strategy to simultaneously enhance its strength and toughness from the perspective of structural optimization and interface enhancement. Inspired by the nacre structure, a 3D-(SiC–Si 3 N 4 )/Al co-continuous composite was prepared by freeze-casting combined with the pressure infiltration method. During the process, elongated Si 3 N 4 grains were introduced into the ceramic framework to design the internal lamella wall structure and increase the contact area with the aluminum substrate. Moreover, a favorable interfacial bonding was designed between Si 3 N 4 and Al to improve interface wettability . The reliable microstructure of porous 3D-(SiC–Si 3 N 4 ) preform was tailored through the adjustment of initial solid loading and the α-Si 3 N 4 component. The effects of initial solid loading and the α-Si 3 N 4 component on the microstructure, interfacial wettability, and mechanical properties of the final composites were investigated. The results showed that the SiC–Si 3 N 4 /Al composites possess high flexural strength (769 MPa) and fracture toughness (15.1 MPa m 1/2 ), which is superior to data reported in general literature. Numerous elongated β-Si 3 N 4 grains are produced on the ceramic skeleton, forming an interlocking structure with the aluminum matrix, which increases the contact area with the aluminum substrate. A chemical reaction layer was formed at the interface of the composite, greatly improving the interfacial bonding strength. This work provides a promising design guideline for developing and optimizing high-strength and tough composite.
研究领域:
材料科学
·
复合材料工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Zhongli Zhang,Zhensheng Wu,Fan Zou,Fuqiang Tian
Polyimide (PI) refers to a polymer containing an imide ring characteristic structure on the main chain. It has excellent thermal stability, insulation properties and other characteristics. The Tesla transformer is the core component of the primary pulse source of the high-current electron beam accelerator. It is also an essential component of the energy storage pulse power supply. Therefore, it has broad application prospects in the fields of national defense and civil industry. If the insulation performance of the turn-to-turn coils of the Tesla transformer does not meet the standards, it will break down during high-voltage corona discharge, causing transformer failure. Therefore, it is crucial to improve the insulation performance of Tesla transformer inter-turn wrapping materials. The incorporation of fluorine-containing groups has proven to be a transformative strategy that significantly enhances the physical, chemical, optical, and electrical properties of PI films. In addition, numerous studies have demonstrated that introducing inorganic fillers into the polyimide matrix can substantially enhance the insulating properties of polyimide films. This paper specifically concentrates on elevating the insulating and thermal attributes of polyimide. Initially, a range of polyimide films was synthesized for performance assessment by employing various fluorinated dianhydride and diamine components, utilizing them as substrates. Then, we used nano-silicon nitride (nano-Si 3 N 4 ) and nano-alumina (nano-Al 2 O 3 ) as doping phases to prepare PI composite films, which reduced the dielectric constant and increased the breakdown strength.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Dapeng Gu,Guanqun Wang,Suwen Chen,Hongtao Luo,Xiaofan Chen,Ziyu Liu
The traditional high-temperature sintering method cannot achieve the combination of ceramics and polymers for the huge sintering temperature difference. The insufficient interfacial bonding strength of the ceramic matrix is the difficulty in the low-temperature preparation of ceramic-polymer composites. To improve the interfacial bonding strength of Si 3 N 4 (Silicon nitride) ceramic matrix composite, an easy-bonding SiO 2 (Silica) shell was introduced onto the surface of the hard-bonding Si 3 N 4 core by Stober method, to obtain Si 3 N 4 @SiO 2 composite. Si 3 N 4 @SiO 2 /PEEK (Polyetheretherketone) composites were prepared by the cold sintering process (500 MPa, 240 °C, and transient liquid phase is NaOH solution). The dry tribological properties of Si 3 N 4 @SiO 2 /PEEK composites with different PEEK percentages were studied by a ball-disc contact form. It is shown that an amorphous SiO 2 shell with a thickness of 25 nm is chemically bonded onto the surface of the Si 3 N 4 core. The presence of the SiO 2 shell improves the interface bonding strength between Si 3 N 4 ceramic particles. The friction coefficients of Si 3 N 4 @SiO 2 /PEEK composites decrease with the increase of PEEK percentage. Compared with Si 3 N 4 @SiO 2 composite, the friction coefficient and wear rate of Si 3 N 4 @SiO 2 /50 vol% PEEK composite decrease by about 40% and 26%, respectively. The main wear forms of Si 3 N 4 @SiO 2 /PEEK composites are abrasive wear and adhesive wear. A mixed lubrication layer, mainly including PEEK, Si 3 N 4 , and SiO 2 , exists simultaneously on the surfaces of Si 3 N 4 @SiO 2 /PEEK composite and the counterpart ball, respectively, playing the role of reducing friction and wear.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Jing Zhang,Changhua Li,Xiaofeng Zhang,Hao Chen,Rui Gou,Chao Zhang,Dan Sun,Yi He
The use of graphene-based materials as anticorrosion coatings to protect metals is always a topic of discussion. In this work, silicon nitride (Si3N4) was aminated to improve its water dispersibility. Then it is attached to the graphene oxide (GO) surface to improve compatibility with epoxy (EP) resin as well as conductivity. The results of Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and zeta potentials test analyses indicated that Si3N4–NH2@GO with a layer-point structure has been successfully prepared. The corrosion resistance of the composite coatings was characterized by electrochemical impedance spectroscopy (EIS) and polarization curve analysis, and the wear resistance of the composite coatings was tested by friction and wear tests. The results showed that 1.0% Si3N4–NH2@GO has excellent corrosion and wear resistance. The use of Si3N4–NH2@GO layer point structures in this study broadens the way for GO applications.
研究领域:
材料科学
·
防腐蚀技术
·
表面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 19
·期 6
·3403-3409
·
IF 2.328
Minzhong Huang,Yao Huang,Jun Ou,Yangyang Wu,Junye Wang,Shanghua Wu
Enhancement of the thermal conductivity of silicon nitride is usually achieved by sacrificing its mechanical properties (bending strength). In this study, β-Si 3 N 4 ceramics were prepared using self-synthesized Y 3 Si 2 C 2 and MgO as sintering additives. It was found that the thermal conductivity of the Si 3 N 4 ceramics was remarkably improved without sacrificing their mechanical properties. The microstructure and properties of the Si 3 N 4 ceramics were analyzed and compared with those of the Y 2 O 3 -MgO additives. The addition of Y 3 Si 2 C 2 eliminated the inherent SiO 2 and introduced nitrogen to increase the N/O ratio of the grain-boundary phase, inducing Si 3 N 4 grain growth, increasing Si 3 N 4 grain contiguity, and reducing lattice oxygen content in Si 3 N 4 . Therefore, by replacing Y 2 O 3 with Y 3 Si 2 C 2 , the thermal conductivity of the Si 3 N 4 ceramics was significantly increased by 31.5% from 85 to 111.8Wm −1 K −1 , but the bending strength only slightly decreased from 704 ± 63MPa to 669 ± 33MPa.
研究领域:
材料科学
·
陶瓷工程
✓ 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）