The effect of fabrication parameters on the mechanical properties of sintered reaction bonded porous Si3N4 ceramics

Porous silicon nitride ceramics were prepared via sintered reaction bonded silicon nitride at 1680°C. The grain size of nitrided Si3N4 and diameter of post-sintered β-Si3N4 are controlled by size of raw Si. Porosity of 42.14–46.54% and flexural strength from 141MPa to 165MPa were obtained. During po...

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Bibliographic Details
Published in:Journal of the European Ceramic Society 2014-12, Vol.34 (15), p.3461-3467
Main Authors: Yao, Dongxu, Xia, Yongfeng, Zuo, Kai-hui, Jiang, Dongliang, Günster, Jens, Zeng, Yu-Ping, Heinrich, Jürgen G.
Format: Article
Language:English
Subjects:
Anisotropic grain growth
Porous ceramics
Reaction bonding
Silicon nitride
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Summary:Porous silicon nitride ceramics were prepared via sintered reaction bonded silicon nitride at 1680°C. The grain size of nitrided Si3N4 and diameter of post-sintered β-Si3N4 are controlled by size of raw Si. Porosity of 42.14–46.54% and flexural strength from 141MPa to 165MPa were obtained. During post-sintering with nano Y2O3 as sintering additive, nano Y2O3 can promote the formation of small β-Si3N4 nuclei, but the large amount of β-Si3N4 (>20%) after nitridation also works as nuclei site for precipitation, in consequence the growth of fine β-Si3N4 grains is restrained, the length is shortened, and the improvement on flexural strength is minimized. The effect of nano SiC on the refinement of the β-Si3N4 grains is notable because of the pinning effect, while the effect of nano C on the refinement of the β-Si3N4 grains is not remarkable due to the carbothermal reaction and increase in viscosity of the liquid phase.
ISSN:0955-2219
1873-619X
DOI:10.1016/j.jeurceramsoc.2014.06.018