Simultaneous improvement in porosity and strength of porous β-Si3N4 ceramics by formation of ultrafine fibrous grains

Zhi, Qiang; Wang, Bo; Zhao, Sheng; Zhang, Zhao; Deng, Yuchen; Hou, Baoqiang; Zhang, Nan–Long; Yang, Jianfeng

doi:10.1016/j.ceramint.2020.11.166

Cited by 10 publications

(5 citation statements)

References 56 publications

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“…It can be observed from Figure S3 that rod‐like β‐Si 3 N 4 grains in the composite grow along the plane (110) 39 . The linear arrangement of electron diffraction spots (Figure S3F) proves that the β‐Si 3 N 4 grains grow along the (110) crystal plane 39,40 . As the content of TiC increased, the porosity gradually increased (Figure 6), which was basically consistent with the test results of all samples in Figure 8B.…”

Section: Resultssupporting

confidence: 82%

“…39 The linear arrangement of electron diffraction spots (Figure S3F) proves that the β-Si 3 N 4 grains grow along the (110) crystal plane. 39,40 As the content of TiC increased, the porosity gradually increased (Figure 6), which was basically consistent with the test results of all samples in Figure 8B. Moreover, the granular TiC grains are uniformly dispersed in porous Si 3 N 4 .…”

Section: Structure Morphology and Mechanical Properties Of Compositessupporting

confidence: 85%

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Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si₃N₄ absorbing composites by gel casting

Liang

Qiao

et al. 2023

Int J Applied Ceramic Tech

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In view of the lack of conformal, load‐bearing, light‐weight, and high temperature‐resistant integrated wave‐absorbing composites suitable for extremely complex conditions, the gel‐casting process was successfully applied to porous Si3N4 wave‐absorbing composites in this work. A universal low‐slurry for gel casting was prepared by using two dispersants acting together (tetramethylammonium hydroxide solution and sodium lauryl sulfate), which ensured the smooth completion of the gel casting process. Combining the thermogravimetric and differential thermal gravity curves of the composite green body, reasonable parameters of the rubber discharge process are given to avoid the problem of the green body swelling and cracking. The porous TiC/Si3N4 composites were successfully prepared by holding them at 1650°C for 3 h. The bending strength, density, minimum reflection loss, absorption bandwidth, and matched thickness in the P‐band of the composites with 30 wt.% TiC addition were 54.08 ± 3.02 MPa, 1.906 g/cm3, ‐37.75 dB, 1.9 GHz, and 4.1 mm, respectively. The electromagnetic wave loss mechanisms of the composites are a combination of conductivity loss, multiple reflections and scattering, interfacial polarization, and defect polarization.

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Section: Resultssupporting

confidence: 82%

Section: Structure Morphology and Mechanical Properties Of Compositessupporting

confidence: 85%

Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si₃N₄ absorbing composites by gel casting

Liang

Qiao

et al. 2023

Int J Applied Ceramic Tech

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“…A high σ 0 and a small B are obtained, by which a ultrahigh strength is achieved in the Al 2 O 3 /YAG/ZrO 2 porous eutectic ceramics. They are compared with the Al 2 O 3 , Si 3 N 4 , and SiC porous ceramics prepared by various current preparation methods (Figure c), which shows that this study sets a new record of the strength of all current porous ceramics. ,− ,,,,− …”

Section: Resultsmentioning

confidence: 76%

Ultrahigh-Strength Porous Ceramic Composites via a Simple Directional Solidification Process

Zhao

Liu

et al. 2022

Nano Lett.

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Porous ceramics possess great application potential in various fields. However, the contradiction between their pores and their strength have significantly hampered their applications. In this study, we present a simple directional solidification process that relies on its in situ pore forming mechanism to fabricate Al 2 O 3 /Y 3 Al 5 O 12 / ZrO 2 porous eutectic ceramic composites with a highly dense and nanostructured eutectic skeleton matrix and a lotus-type porous structure. The flexural strength of this porous ceramic composite with a porosity of 34% is 497 MPa at ambient temperature, which is a new record of the strength of all current porous ceramics. This strength can remain at 324 MPa when the temperature increases up to 1773 K because of its refined lamellar structure and strong bonding interface. We demonstrate an interesting application of the directional solidification in efficiently preparing the ultrahigh-strength porous ceramic with high purity. The findings will open a window to the strength of porous ceramics.

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“…Porous Si 3 N 4 ceramics with a cellular structure, especially with unidirectionally aligned channels are promising candidates for hot gas or molten metal filtration, separation membranes, and catalyst carriers because of their excellent mechanical properties and gas permeability, high temperature stability, and outstanding thermal shock resistance [1][2][3][4]. Generally, these cellular ceramics are prepared by the sintering of the green body with unidirectionally aligned channels [5].…”

Section: Introduction mentioning

confidence: 99%

Anisotropic, biomorphic cellular Si3N4 ceramics with directional well-aligned nanowhisker arrays based on wood-mimetic architectures

Zhou

Zhi

et al. 2022

J Adv Ceram

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Inspired by the transport behavior of water and ions through the aligned channels in trees, we demonstrate a facile, scalable approach for constructing biomorphic cellular Si3N4 ceramic frameworks with well-aligned nanowhisker arrays on the surface of directionally aligned microchannel alignments. Through a facile Y(NO3)3 solution infiltration into wood-derived carbon preforms and subsequent heat treatment, we can faultlessly duplicate the anisotropic wood architectures into free-standing bulk porous Si3N4 ceramics. Firstly, α-Si3N4 microchannels were synthesized on the surface of CB-templates via carbothermal reduction nitridation (CRN). And then, homogeneous distributed Y−Si−O−N liquid phase on the walls of microchannel facilitated the anisotropic β-Si3N4 grain growth to form nanowhisker arrays. The dense aligned microchannels with low-tortuosity enable excellent load carrying capacity and thermal conduction through the entire materials. As a result, the porous Si3N4 ceramics exhibited an outstanding thermal conductivity (TC, kR ≈ 6.26 W·m−1·K−1), a superior flexural strength (σL ≈ 29.4 MPa), and a relative high anisotropic ratio of TC (kR/kL = 4.1). The orientation dependence of the microstructure-property relations may offer a promising perspective for the fabrication of multifunctional ceramics.

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Simultaneous improvement in porosity and strength of porous β-Si3N4 ceramics by formation of ultrafine fibrous grains

Cited by 10 publications

References 56 publications

Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si₃N₄ absorbing composites by gel casting

Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si₃N₄ absorbing composites by gel casting

Ultrahigh-Strength Porous Ceramic Composites via a Simple Directional Solidification Process

Anisotropic, biomorphic cellular Si3N4 ceramics with directional well-aligned nanowhisker arrays based on wood-mimetic architectures

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Simultaneous improvement in porosity and strength of porous β-Si3N4 ceramics by formation of ultrafine fibrous grains

Cited by 10 publications

References 56 publications

Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si3N4 absorbing composites by gel casting

Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si3N4 absorbing composites by gel casting

Ultrahigh-Strength Porous Ceramic Composites via a Simple Directional Solidification Process

Anisotropic, biomorphic cellular Si3N4 ceramics with directional well-aligned nanowhisker arrays based on wood-mimetic architectures

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Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si₃N₄ absorbing composites by gel casting

Preparation and properties of lightweight, conformal, and load‐bearing TiC/Si₃N₄ absorbing composites by gel casting