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Porous Si3N4 ceramics were prepared by aqueous gelcasting using Si3N4 poly-hollow microspheres (PHMs) as pore-forming agent. The effects of solid loading of Si3N4 slurry and Si3N4 PHM content on the properties of porous Si3N4 ceramics were investigated. Only β-Si3N4 phase is observed in porous Si3N4 ceramics, and Si3N4 PHMs distribute uniformly both in Si3N4 green samples and porous Si3N4 ceramics. Results show that solid loading of Si3N4 slurry and Si3N4 PHM content could considerably influence the properties of porous Si3N4 ceramics. With the increase of solid loading of Si3N4 slurry (decrease of Si3N4 PHM content), the distributing state of Si3N4 PHMs changes from contacting with each other to just embedding in the matrix, thus their porosity decreases, while their shrinkage, flexural strength, and fracture toughness increase.


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Preparation of porous Si3N4 ceramics via tailoring solid loading of Si3N4 slurry and Si3N4 poly-hollow microsphere content

Show Author's information Jia-Min WUa,bXiao-Yan ZHANGbJie XUbKe GANbJia-Lu LIbChen-Hui LIa( )Jin-Long YANGb( )Yu-Sheng SHIa
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
State Key Laboratory of New Ceramic and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China

Abstract

Porous Si3N4 ceramics were prepared by aqueous gelcasting using Si3N4 poly-hollow microspheres (PHMs) as pore-forming agent. The effects of solid loading of Si3N4 slurry and Si3N4 PHM content on the properties of porous Si3N4 ceramics were investigated. Only β-Si3N4 phase is observed in porous Si3N4 ceramics, and Si3N4 PHMs distribute uniformly both in Si3N4 green samples and porous Si3N4 ceramics. Results show that solid loading of Si3N4 slurry and Si3N4 PHM content could considerably influence the properties of porous Si3N4 ceramics. With the increase of solid loading of Si3N4 slurry (decrease of Si3N4 PHM content), the distributing state of Si3N4 PHMs changes from contacting with each other to just embedding in the matrix, thus their porosity decreases, while their shrinkage, flexural strength, and fracture toughness increase.

Keywords:

porous Si3N4 ceramics, Si3N4 poly-hollow microspheres (PHMs), solid loading, aqueous gelcasting, mechanical properties
Received: 21 February 2015 Revised: 07 June 2015 Accepted: 12 June 2015 Published: 21 September 2015 Issue date: April 2015
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Publication history

Received: 21 February 2015
Revised: 07 June 2015
Accepted: 12 June 2015
Published: 21 September 2015
Issue date: April 2015

Copyright

© The author(s) 2015

Acknowledgements

Our research work presented in this paper was supported by China Postdoctoral Science Foundation (Nos. 2013M530618 and 2015M572136), National Natural Science Foundation of China (Nos. 51172120 and 51372093), Fundamental Research Funds for the Central Universities (HUST: 2015J07), Open Fund of State Key Laboratory of New Ceramic and Fine Processing (Tsinghua University) (No. KF201518) and the 02 Important and Special Project for the State Science and Technology (No. 2013ZX2104-001-002).

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