CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xingjie Dong,Jianqin Wu,Qing Zhou,Wenqing Wang,Xueqin Zhang,Lu Zhang,Rujie He
Si 3 N 4 -SiO 2 ceramics are considered as the preferred high-performance wave-transmitting material in the aerospace field. However, traditional fabrication methods for Si 3 N 4 -SiO 2 ceramics have the disadvantages of high cost and complicated fabrication process. In this paper, Si 3 N 4 -SiO 2 ceramics with excellent mechanical and dielectric properties were fabricated by digital light processing-based 3D printing combined with oxidation sintering. Firstly, the curing thickness and viscosity of slurries with different solid loadings for vat photopolymerization-based 3D printing were studied. Then, the effects of the sintering temperature on the linear shrinkage, phase composition, microstructure, flexural strength , and dielectric properties of Si 3 N 4 -SiO 2 ceramics, and the influences of solid loading on them were explored. The curing thickness and viscosity of the slurry with a solid loading of 55 vol% were 30 μm and ∼1.5 Pa‧s, respectively. The open porosity and the flexural strength of Si 3 N 4 -SiO 2 ceramic with a solid loading of 55 vol% were 4.3 ± 0.61% and 76 ± 5.6 MPa, respectively. In the electromagnetic wave band of 8–18 GHz, the dielectric constant of Si 3 N 4 -SiO 2 ceramics was within the range of less than 4, and the dielectric loss remained below 0.09. The method of digital light processing-based 3D printing combined with oxidation sintering can be further extended in the preparation of Si 3 N 4 -based structure-function integrated ceramics.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Shengwu Huang,Yanhui Li,Ping Yang,Pengfei Sheng,Jun Ou,Turui Ning,Shanghua Wu
Digital light processing is a vital additive manufacturing technology used for manufacturing ceramic parts. The particle size distribution of ceramic suspensions significantly affects the cure behaviour and mechanical properties of ceramics. In this study, the cure behaviour and mechanical properties of Si 3 N 4 ceramics with a bimodal particle size distribution were studied. The results indicated that the suspension with coarse particles had a higher cure depth for a lower absorbance but poor mechanical properties. The bending strength of the samples with the optimal ratio (coarse:fine particles = 3:7) reached a maximum of 728.7 ± 10.33 MPa, which is 16.5% higher than that of the samples prepared using only fine particles.
研究领域:
材料科学
·
增材制造
·
陶瓷工程
✓ 已验证
DOI
高影响因子
VACUUM
·
2025
·
IF 3.9
Xiaoli Ji,Fan Chen,Jian Liu,Qianqian Ma,Zhihao Xu,Ruochen Qiao
In this paper, MWCNTs/Si 3 N 4 binary composites were synthesized using a chemical click method, establishing a foundation for the in situ polymerization of MWCNTs/Si 3 N 4 /PPy ternary composites. The morphology, electrical conductivity, and electromagnetic parameters of the composites were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and infrared analysis. The wave-absorbing properties of the composites were assessed with a vector network analyzer. The impact of varying feeding ratios on the absorption properties of the composites was investigated. The results indicated that as the amount of PPy increased, the minimum reflection loss of the nano-hybrid materials initially decreased before subsequently increasing. When the feeding ratio of MWCNTs: Si 3 N 4 : PPy was set at 2:1:4 and the thickness of the absorption layer was 2.5 mm, the minimum reflection loss (RL min ) reached −40.14 dB, while the maximum absorption bandwidth (EAB max ) attained 6.88 GHz (d = 2.0 mm). Compared to MWCNTs/Si 3 N 4 binary materials, the ternary materials demonstrated enhanced electromagnetic absorption capabilities. The numerous heterogeneous interface formed by MWCNTs, Si 3 N 4 , and PPy facilitates charge accumulation, creating a structure similar to a capacitor that induces interface polarization and attenuates electromagnetic waves (EMWs) by aligning polar bonds or charges in response to an alternating electric field. Additionally, the MWCNTs/Si 3 N 4 binary nanohybrid materials exhibit a larger surface area following PPy coating, which further enhances impedance matching, extends the propagation distance of EMWs, and improves their dissipation. These research results are of great significance for the production of absorbent composite materials and provide new ideas for the design of absorbent materials.
研究领域:
材料科学
·
纳米技术
·
电磁学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Guandong Liang,Jianqiang Bi,Linjing Qiao,Shaoyin Wang,Yao Yang,Zhuangzhuang Yin
In view of the lack of a conformal, load-bearing, lightweight, and high-temperature resistant integrated microwave-absorbing composites for applications under extremely complex conditions, this study successfully applies gel casting craft to porous Si 3 N 4 microwave-absorbing composites. The high-temperature decomposition reaction of Ti 3 SiC 2 powder was utilized to generate uniform Ti-C x -N 1−x grains in situ and to enhance the mechanical and microwave-absorption properties of porous Ti-C x -N 1−x /Si 3 N 4 composites. The bending strength , fracture toughness, density, maximum reflection loss value, absorption bandwidth and matched thickness in P-band of the composite with 30 wt% Ti 3 SiC 2 addition were 164.87 ± 7.56 MPa, 2.61 ± 0.13 MPa·m 1/2 , 2.077 g/cm 3 , 32.42 dB, 1.74 GHz and 4.2 mm, respectively. The fracture toughness and bending strength of the composite were increased by 71.71% and 58.13%, respectively, compared with monolithic porous Si 3 N 4 . The electromagnetic wave loss mechanisms of the composites are proposed as a combination of conductivity loss, multiple reflections and scattering, interfacial polarization and defect polarization.
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 SOL-GEL SCIENCE AND TECHNOLOGY
·
2022
·Vol. 104
·期 1
·105-115
·
IF 2.606
Yang Haixia,Yue Xiandong,Ye Feng
Porous Si 3 N 4 /silica aerogel composites were prepared by sol impregnation with porous Si 3 N 4 as the framework, and the microstructure evolution and properties of the composites were studied in detail at high temperature. Porous Si 3 N 4 had a strong skeleton structure, which effectively inhibited the pore collapse of the aerogel, kept the nanostructure stable to 1100 °C, and significantly improved the temperature resistance of the silica aerogel. Preventing the growth of gel particles and pore collapse at temperatures above 1100 °C was difficult, and the silica aerogel gradually crystallised. When the temperature reached 1300 °C, the aerogel inside was completely crystallised, and the nanopore structure basically disappeared. The specific surface area of the composite decreased with increasing temperature, whereas the pore size and thermal conductivity increased with increasing temperature. The high-temperature thermal insulation performance was tested, and the composite material exhibited low thermal conductivity (0.254 W m −1 K −1 ) at even 1300 °C, which suggests this composite is suitable for thermal insulation use in a high-temperature environment.
Graphical abstract
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
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Qiang Zhi,Bo Wang,Shan Zhao,Zhao Zhang,Yu-Chen Deng,Bao-Qiang Hou,Nan-Long Zhang,Jian-Feng Yang
Si 3 N 4 ceramic with ultrafine fibrous grains are expected to exhibit remarkable mechanical properties . In this work, highly porous Si 3 N 4 ceramic monoliths composed of ultrafine fibrous grains were developed via a novel vapor-solid carbothermal reduction nitridation (V-S CRN) reaction between SiO vapor and green bodies comprised of carbon nanotubes (CNTs), α-Si 3 N 4 diluents and Y 2 O 3 in a N 2 atmosphere. The unique fibrous grains-interconnected structure was developed through in-situ formation of Si 3 N 4 and following liquid phase sintering . The porous Si 3 N 4 monoliths with porosity of 61–78% was developed by controlling the contents of α-Si 3 N 4 diluents and densities of the CNT green bodies. With increasing of the α-Si 3 N 4 contents, Si 3 N 4 fibrous grains with an aspect ratio of approximate or higher than 20 could be achieved, and the grains were gradually refined. For the samples with 40 wt% α-Si 3 N 4 , the minimum mean grain diameter and pore size of 164 nm and 0.79 μm were achieved, respectively, and the resultant porous Si 3 N 4 monolith exhibited a flexural strength of as high as 73–102 MPa with the porosity of 61–73%, which is much higher than that of the reported in literature. The improvement of mechanical strength could be attributed to the densely interconnected bird's nests structure formed by the ultrafine fibrous grains. The effects of the α-Si 3 N 4 diluents on the resulting porous Si 3 N 4 monolith via this method were analyzed.
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
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Shuang Yin,Senchuan Jiang,Limei Pan,Chao Liu,Yongbao Feng,Tai Qiu,Jian Yang
In this work, Si 3 N 4 ceramics were fabricated through an aqueous gelcasting method using a low–toxic monomer called N, N–dimethylacrylamide (DMAA) followed by gas pressure sintering at 1850 °C for 2 h under 6 MPa N 2 atmosphere. The effect of solid loading on performance of slurries, green and sintered bodies was investigated systematically. The results show that the slurries with a solid loading as high as 50 vol% (viscosity 0.17 Pa.s at 100 s –1 ) were achieved. With the increase of solid loading (30–50 vol%), the green bodies exhibited a monotonically decreased, however high enough in general, flexural strength of 16.50–11.52 MPa, which was comparable to that of widely–used neurovirulent acrylamide (AM) gelling system. In regard to the sintered bodies, increasing solid loading significantly promoted sintering and improved mechanical properties and thermal conductivity as a result of the increased density, bimodal distribution structure, as well as suitable interfacial bonding strength . The best performance parameters of Si 3 N 4 ceramics, bulk density of 3.25 g/cm 3 , apparent porosity of 0.67%, flexural strength of 898.92 MPa, fracture toughness of 6.42 MPa m 1/2 , Vickers hardness of 2.81 GPa, and thermal conductivity of 34.69 W m –1 K –1 , were obtained at 50 vol% solid loading. This work renders low–toxic DMAA gelling system promising prospect in preparation of high–performance Si 3 N 4 ceramics by gelcasting.
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 EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Heng Zhang,Dongxu Yao,Ming Zhu,Yongfeng Xia,Jun Zhao,Yu-Ping Zeng
Porous Si 3 N 4 ceramics hold great promise for high-temperature wave-transparent materials, but it is a significant challenge to achieve both a low dielectric constant and high mechanical strength. This study explores a method combining in-situ pre-gel casting and non-directional freeze-drying to produce high-porosity, uniform microstructure Si 3 N 4 ceramics. By adjusting gel concentration and pre-gelation time, ice crystal growth effectively restricted, resulting in a uniform pore structure. The resulting porous Si 3 N 4 ceramics exhibited low drying shrinkage (1.50 %) and high porosity (59.13 %), with a flexural strength of 119.48 MPa, surpassing porous ones produced by other wet forming processes. At 30 GHz, the dielectric constant was 2.45, and the dielectric loss was 5.65 × 10 −3 .
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 ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Ziqiang Jiang,Laian Sheng,Jingtian Li,Guodong Sun,Weihua Luo,Peng Zhao
In present work, Ce 3 + -doped Y 3 Al 5 O 12 (YAG: Ce) transparent ceramics were fabricated via spark plasma sintering (SPS) using Si 3 N 4 as a multifunctional sintering additive. The effects of Si 3 N 4 on the microstructure, densification behavior, and luminescent properties were systematically investigated. It is demonstrated that Si 3 N 4 could be effectively incorporated into the YAG lattice through a charge-balanced substitution mechanism in which Si 4+ -N 3- pairs replace Al 3+ -O 2- , resulting in a significant redshift of the Ce 3+ emission from 545 nm to 582 nm due to enhanced crystal field splitting and nephelauxetic effects. Furthermore, the substitution process also yields in-situ formation of SiO 2 , which promotes densification via liquid-phase sintering, achieves a relative density exceeding 99.5 %, and partially mitigates carbon contamination. When applied in phosphor-converted white LEDs, the Si 3 N 4 -doped YAG: Ce ceramics enabled a substantial reduction in correlated color temperature (CCT) from 4903 K to 3196 K, demonstrating their potential as efficient warm-white light converters without requiring additional red phosphors.
研究领域:
材料科学
·
无机非金属材料
·
发光材料
·
固态照明
·
陶瓷工艺
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xiaoyu Zhang,Yuanyuan Zhu,Fu Wang,Kang Deng,Zhilei Wei,Xiangyang Xu,Jihua Chen,Zhongqi Shi
Si 3 N 4 -skeleton-reinforced graphite flake (GF/Si 3 N 4 ) composites with preferred orientation were fabricated using a combination of vacuum infiltration and plasma-activated sintering to produce highly oriented graphite-based composites with excellent strength, favorable thermal conductivity, low thermal expansion, and effective electromagnetic shielding properties. The impact of Si 3 N 4 content on the microstructure, bending strength, thermophysical properties, and electromagnetic shielding effectiveness of the composites was systematically examined. The composites exhibited reasonable anisotropy (Lotgering factor f > 93 %), endowing them with high thermal conductivity in the basal plane direction of the GF. The formation of SiC at the Si 3 N 4 /GF interface increased the interfacial bonding and effectively suppressed the thermal expansion of GF perpendicular to the basal plane from ∼28 × 10 −6 /K to ∼8 × 10 −6 /K. The composite with 21 vol.% Si 3 N 4 exhibited the optimal properties, including a satisfactory bending strength of 128 MPa, good thermal conductivity of 247 W/m/K, a suitable thermal expansion of 9.4 × 10 −6 /K, and good electromagnetic interference shielding effectiveness of 30 dB. Hence, the fabricated GF/Si 3 N 4 composites demonstrate significant potential as high-orientation graphite-based composites for multifunctional thermal management.
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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 1
·122-135
·
IF 3.094
Jingkun Xu,Zunlan Hu,Yao Han,Di An,Zhipeng Xie
In the present work, high-quality MgSiN 2 powders were prepared by a combustion synthesis method, based on Mg-Si 3 N 4 -N 2 system. The effects of additive content (NH 4 Cl or NH 4 F) and N 2 pressure on phase composition and crystal morphology of products were investigated. The results suggested that both NH 4 Cl and NH 4 F additives alleviated agglomeration and decreased the grain size of MgSiN 2 . In addition, NH 4 Cl did not result in the formation of an extra impurity, while MgF 2 residue was found when NH 4 F was introduced. Therefore, NH 4 Cl additive was considered as a better choice for the preparation of MgSiN 2 powders in comparison with NH 4 F additive. According to the observation of some MgSiN 2 whiskers and notably increased Si content under low N 2 pressure, the pressure of N 2 over 0.5 MPa was essential to have a complete reaction in the present work. Finally, MgSiN 2 -Si 3 N 4 composite powders with quasi-spherical morphology were prepared by adding excessive Si 3 N 4 and NH 4 Cl additive in reactant. The formation and growth mechanism of MgSiN 2 grains was reasonably speculated based on the experimental results. Because of the remarkable merits, the as-prepared Si 3 N 4 -MgSiN 2 composite powders showed great potential for alternative sintering aid in the sintering of Si 3 N 4 -based ceramics.
研究领域:
材料科学
·
陶瓷
·
合成方法
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 107
·期 9
·5810-5824
·
IF 3.5
Shaoyin Wang,Jianqiang Bi,Guandong Liang,Linjing Qiao,Yao Yang,Hongyi Wang,Shuyong Liang,Jiacheng Rong,Chengjiao Che,Jilie Yuan,Yueguang Chen
The aim of achieving integration of lightweight, high strength, high-temperature resistant, and satisfactory electromagnetic (EM) wave absorption was successfully accomplished in the present study by synthesizing TiC–TiB 2 fibers reinforced Si 3 N 4 composites, which were pressureless sintered at 1650°C for 2 h. The preparation of TiC–TiB 2 fibers was conducted through a chloride-assisted carbothermic method. This work focused on investigating the effects of incorporating TiC–TiB 2 fibers on the mechanical properties and EM wave absorption characteristics of the composites. The 30 wt% TiC–TiB 2 /Si 3 N 4 composite displayed the bulk density of 1.89 g/cm 3 , bending strength of 93.11 ± 3.91 MPa, fracture toughness of 1.81 ± 0.10 MPa m 1/2 , minimum reflection loss of −38.87 dB, and effective absorption bandwidth of 1.43 GHz in the K u -band, respectively. The as-synthesized TiC–TiB 2 /Si 3 N 4 composites are promising candidates for EM wave absorbing load-bearing materials due to their outstanding mechanical properties and microwave absorption properties.
研究领域:
材料科学
·
电磁工程
·
机械工程
✓ 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）