One-pot foam-gelcasting/nitridation synthesis of high porosity nano-whiskers based 3D Si3N4 porous ceramics |
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Authors: | Lei Han Yu Chen Hong Chang Faliang Li Cheng Liu Tommy Shyng Yanqiu Zhu Guangqiang Li Haijun Zhang Quanli Jia Shaowei Zhang |
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Affiliation: | 1. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, 430081, China;2. College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, UK;3. Henan Key Laboratory of High Temperature Functional Ceramics, Zhengzhou University, Zhengzhou, 450052, China |
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Abstract: | Nano-whiskers based 3D Si3N4 porous ceramics (3D-NWSNPC) with high-porosity (about 91–93 %), low density (0.17–0.25 g/cm3), low thermal conductivity, and a certain degree of recoverability under cyclic compressive loading and reasonably strengths were prepared at 1423–1523 K via a one-pot foam-gelcasting/nitridation route using inexpensive commercial Si powders as starting materials and hexadecyl trimethyl ammonium bromide as foaming agent. After nitridation at 1523 K, the sample with an original solid loading of 12.5 wt% exhibited the highest compressive strength of 1.9 MPa, even though its density was lowered to 0.25 g/cm3. The sample nitrided at 1473 K had a relative density of 7.3 %. Its compressive and specific strength were respectively 1.1 MPa and 5.5 MPa·cm3 g?1, and its thermal conductivity was as low as 0.074 W/(m K) (measured at 323 K). These outstanding properties would make the as-prepared 3D-NWSNPC a promising candidate for applications in catalysis, filtration, thermal insulation and many other important areas. |
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Keywords: | One-pot synthesis Foam-gelcasting/nitridation High porosity Nano-whiskers |
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