CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Chao Wang,Xu Wang,Binglei Wang,Guozheng Xiao,Ruiqing Qiao,Fan Zhang,Yu Bai,Yizhuo Li,Yusheng Wu,Zhanjie Wang,Hongjie Wang
A dense β-Si 3 N 4 coating toughened by β-Si 3 N 4 nanowires/nanobelts was prepared by a combined technique involving chemical vapor deposition and reactive melt infiltration to protect porous Si 3 N 4 ceramics in this work. A porous β-Si 3 N 4 nanowires/nanobelts layer was synthesized in situ on porous Si 3 N 4 ceramics by chemical vapor deposition, and then Y–Si–Al–O–N silicate liquid was infiltrated into the porous layer by reactive melt infiltration to form a dense composite coating . The coating consisted of well-dispersion β-Si 3 N 4 nanowires/nanobelts, fine β-Si 3 N 4 particles and small amount of silicate glass . The testing results revealed that as-prepared coating displayed a relatively high fracture toughness, which was up to 7.9 ± 0.05 MPa m 1/2 , and it is of great significance to improve thermal shock resistance of the coating. After thermal cycling for 15 times at ΔT = 1200 °C, the coated porous Si 3 N 4 ceramics still had a high residual strength ratio of 82.2%, and its water absorption increased only to 6.21% from 3.47%. The results will be a solid foundation for the application of the coating in long-period extreme high temperature environment.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Zhongya Zhang,Lijuan Zhang,Guangwu Wen,Yongzhao Hou,Nannan Zhu,Cheng Zhong,Jing Xue,Chuncheng Wei,Shuang Li
In this paper, polysilazane photocurable slurry with low viscosity and excellent rheological properties was prepared with β-Si 3 N 4 filler. Digital light processing (DLP) technique was utilised to form green bodies through optimized printing parameters. It was found that the introduction of β-Si 3 N 4 filler reduced the shrinkage and improved the mechanical properties of the polysilazane derived SiCN ceramics. The flexural strength of the resulted ceramics reached a maximum of 253.0 ± 15.1 MPa while 20 wt% of β-Si 3 N 4 powder was added, and the fracture toughness increased to 3.1 ± 0.3 MPa m 1/2 at 30 wt% of the β-Si 3 N 4 powder addition. The shape of the introduced β-Si 3 N 4 particles were believed to be faveriable for uniform dispersion in the printing slurry without agglomeration. In the following pyrolysis treament the β-Si 3 N 4 powders promoted the release of gaseous products so that maintained the structure integrety of the printed parts and the rod-like β-Si 3 N 4 particles enhanced the energy dissipation during ceramic fracture. In this study, silicon-based composite of β-Si 3 N 4 /SiCN ceramics with excellent mechanical properties were prepared by DLP additive manufacturing technology, which confirmed the feasibility and the great potential of photo-curing additive manufacturing technology in the manufacturing of SiCN ceramic matrix composites with complex structures.
研究领域:
材料科学
·
机械工程
✓ 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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 10
·5567-5572
·
IF 3.502
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
A two-step sintering process was conducted to produce β-Si 3 N 4 ceramics with high thermal conductivity. During the first step, native SiO 2 was eliminated, and Y 2 O 3 was in situ generated by a metal hydride reduction process, resulting in a high Y 2 O 3 /SiO 2 ratio. The substitution YH 2 for Y 2 O 3 endow Si 3 N 4 ceramics with an increase of 29% in thermal conductivity from 95.3 to 123 W m −1 K −1 after sintered at 1900°C for 12 hours despite an inferior sinterability. This was primarily attributed to the purified enlarged grains, devitrified grain boundary phase, and reduced lattice oxygen content in the YH 2 -MgO-doped material.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 19
·期 5
·2533-2544
·
IF 2.328
Changxi Jiang,Yinghua Zhuang,Jianjun Wang,Shengjun Liao,Lijuan Zhou,Shuang Li,Yunxia Zhao
Si 3 N 4 ceramics with high thermal conductivity and outstanding mechanical properties were prepared by adding β-Si 3 N 4 seeds and nanophase α-Si 3 N 4 powders as modifiers. The introduction of β-Si 3 N 4 seeds enhanced the growth of β-Si 3 N 4 grains. Owing to the interlocked structure induced by the β-Si 3 N 4 grains, the fracture toughness of Si 3 N 4 ceramics reached a high value of 7.6 MPa·m 1/2 ; also, the large-sized grains increased the contact possibility of Si 3 N 4 grains, improving the thermal conductivity of Si 3 N 4 ceramics (64 W/(m·K)). Because of the introduction of nanophase α-Si 3 N 4 , the flexural strength, fracture toughness, and thermal conductivity of the Si 3 N 4 ceramics increased to 754 MPa, 7.2 MPa·m 1/2 , and 54 W/(m·K), respectively. According to the analysis of the growth kinetics of Si 3 N 4 grains, the rapid growth of Si 3 N 4 grains was ascribed to the reduction in the activation energy resulting from the introduction of β-Si 3 N 4 seeds and nanophase α-Si 3 N 4 .
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 MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Qiang Zhi,Shan Zhao,Baoqiang Hou,Nanlong Zhang,Feng Li,Bo Wang,Jianfeng Yang
Highly porous Si 3 N 4 ceramics with unidirectionally aligned pore channels are gaining significant attention across various fields due to their outstanding functional capabilities. However, achieving high strength in such unidirectional highly porous Si 3 N 4 ceramics remains challenging. Herein, we design and fabricate a novel β-Si 3 N 4 scaffold composed of directionally aligned lamellar walls with a textured microstructure by directionally freeze casting of α-Si 3 N 4 suspensions with fine elongated β-Si 3 N 4 seeds addition, followed by liquid phase sintering. During the sintering, the scaffold exhibited anisotropic shrinkage, and fibrous β-Si 3 N 4 grains were synthesized through epitaxial growth on the seeds preferentially oriented or the nuclei originated from α-Si 3 N 4 powders, resulting in the grains aligned parallel to lamellar walls and bridged the walls. Seed additions of 7 to 15 wt% were beneficial for the optimized distribution of the two types of β-Si 3 N 4 grains, which contributed to the excellent resistance to bucking-induced fracture for the walls. Compared with other unidirectional porous Si 3 N 4 prepared by freeze-casting in the literature, the Si 3 N 4 scaffold exhibited outstanding compressive strength, ranging from 2.8 to 22.0 MPa, as the porosity decreased from 94.4% to 88.0% and the density increased from 175 to 365 mg/cm 3 . The lightweight and strong Si 3 N 4 scaffolds are promising candidates for engineering applications in harsh environments.
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
·
2024
·
IF 5.1
Guang-Xin Mao,Jia-Min Wu,Chong Tian,Chun-Lei Liu,Xin Lin,Fen Wang,Hai-Sheng Xu,Yu-Sheng Shi
Porous Si 3 N 4 ceramics are widely applied in aerospace and mechanical fields owing to their excellent properties. Furthermore, vat photopolymerization (VPP) technology can fabricate Si 3 N 4 components with complicated structures and high precision, but its layer-by-layer printing method leads to poor mechanical properties of ceramics. In this study, porous Si 3 N 4 ceramics with a porosity of 28.41 % strengthened by directional β-Si 3 N 4 were fabricated by combining VPP technology and seeding method. Rheological behavior and curing properties of the slurry were explored, and the influence of β-Si 3 N 4 content on the mechanical properties of printed Si 3 N 4 ceramics was investigated systematically. With the increase of β-Si 3 N 4 content, the orientation degree of β-Si 3 N 4 grains increased gradually, while fracture toughness and flexural strength of the ceramics exhibited a trend of increased first and then decreased and Vickers hardness gradually decreased. As β-Si 3 N 4 content increased to 5 wt%, the fracture toughness and flexural strength of porous Si 3 N 4 ceramics were improved from 4.23 MPa m 1/2 and 214.7 MPa–5.65 MPa m 1/2 and 272.0 MPa, respectively. Therefore, this work indicates that vat photopolymerization combined with seeding method is a promising approach for the fabrication of porous Si 3 N 4 ceramics with high performance and complex structures.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Qiang Zhi,Shan Zhao,Nan-Long Zhang,Bao-Qiang Hou,Bo Wang,Jian-Feng Yang
The directional freezing of β-Si 3 N 4 whiskers suspensions followed by high-temperature sintering was employed for fabricating novel highly porous fibrous Si 3 N 4 three-dimensional (3D) scaffolds. A honeycomb-like structure was achieved, in which the directionally aligned lamellar walls were composed of the oriented fibrous Si 3 N 4 grains and bridged by the transverse grains. Ultrahigh porosities ranging from 97.8% to 90.2% and rather low densities from 0.073 to 0.320 g cm −3 could be obtained by controlling the Si 3 N 4 contents from 1.5 to 7.5 vol%. The longitudinal compressive strength was superior to the transverse and increased obviously from 0.19 to 3.7 MPa as the porosity decreased. The superior compressive strength was due to the excellent resistance to bucking-induced elastic instability for the lamellar fibrous Si 3 N 4 walls. Meanwhile, the dielectric constant and loss were decreased to 1.08 and 6.6 × 10 −4 , respectively. This study provides a strategy for fabricating porous Si 3 N 4 ceramics with ultrahigh porosities and improved strength.
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
Yaru Qin,Chenyu Zhao,Yujie Huang,Jiguang Dong,Xingyu Yang,Chenglong Shi
Porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics are anticipated to serve as high-temperature wave-transparent materials, yet the fabrication of high-performance porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics remains a significant challenge. Addressing this issue, this study introduces a technique for crafting high-performance porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics. This method involves the homogeneous blending of SiO 2 and Si 3 N 4 powders, followed by digital light processing and high-temperature liquid-phase sintering at 2000 °C. The impact of SiO 2 content on various properties of the ceramic slurry and the resultant ceramics was thoroughly examined, including rheology, curing depth, microstructural morphology, phase composition, flexural strength, hardness, dielectric constant, and dielectric loss. It was observed that a SiO 2 content of 30 % enables the slurry to fulfill the criteria for digital light processing, leading to the production of porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics that exhibit outstanding mechanical and dielectric properties. Specifically, these ceramics demonstrated a flexural strength of 149.2 ± 7.2 MPa and a hardness of 11.8 ± 1.1 GPa. Moreover, at a frequency of 10 GHz, the ceramics exhibited a dielectric constant of 4.02 and a dielectric loss of 0.11, highlighting their potential as high-temperature wave-transparent materials.
研究领域:
材料科学
·
陶瓷工程
·
电子材料
✓ 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
Jia Hongsheng,Li Jiaqi,Niu Rui,Ye Chaochao,Ru Hongqiang,Liu Baochang,E. Yuanlong,Li Haibo
In this work, the Silicon nitride composite ceramics (β-Si 3 N 4 ) by ultra-high pressure sintering were investigated. And the effect of sintering temperature , hold time and α-Si 3 N 4 powders on the sintering process had been analyzed in detail. These experimental results showed the larger particle size and lower porosity had an obvious effect on the thermal conductivity . Meanwhile, the addition of α-Si 3 N 4 powder could be also attributed to thermal conductivity. We had been calculated the porosity of β-Si 3 N 4 composite ceramics that the sample D (0.26%) was lower than the others samples. For a comparison, the thermal conductivity of sample D was up to 64.6 W/m K that was also attributed to its higher diffusion rate and small grain size.
研究领域:
材料科学
·
热传导工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2020
·
IF 4.419
Yang Chen,Chengji Deng,Xing Wang,Jun Ding,Chao Yu,Hongxi Zhu
Si 3 N 4 -MgO-C refractories were prepared using fused magnesia, flake graphite, and Si powder-supported Fe(NO 3 ) 3 ·9H 2 O as the raw materials and phenolic resin as the binder under the flow of N 2 . The effect of different nitriding temperatures on the morphology and production of Si 3 N 4 in the uncatalyzed refractories was investigated. The effect of the morphology of β-Si 3 N 4 on the properties of the refractories with different catalyst contents was investigated. The oxidation resistance of the refractories was also investigated. The results showed that the increase in the nitriding temperature was beneficial for the formation of β-Si 3 N 4 in the refractories. However, very high nitriding temperatures generated a large number of pores in the refractories and deteriorated their properties. The refractory with 1 wt% catalyst exhibited good mechanical properties and oxidation resistance. However, the addition of excessive catalyst inhibited the formation of β-Si 3 N 4 and deteriorated the performance of the refractories.
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
危险品化学品经营许可证（带存储）