The Effects of BN Addition on the Mechanical Properties of Porous Si3N4/BN Ceramics Prepared Via Nitridation of Silicon Powder

Authors

  • Dongxu Yao,

    1. Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
    2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China
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  • Yu-Ping Zeng,

    Corresponding author
    1. Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
    2. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
      †Author to whom correspondence should be addressed. e-mail: yuping-zeng@mail.sic.ac.cn
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  • Kai-Hui Zuo,

    1. Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
    2. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
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  • Dongliang Jiang

    1. Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
    2. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
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  • M. Mueller—contributing editor

  • This work was supported by National Natural Science Foundation of China (No. 5087214 and No.50902140).

†Author to whom correspondence should be addressed. e-mail: yuping-zeng@mail.sic.ac.cn

Abstract

Porous Si3N4/BN ceramics were prepared via nitridation of silicon powder, with Si and BN as starting powder, Y2O3 as sintering additive. After nitridation and sintering at 1680°C, porous Si3N4/BN ceramics with a porosity of 47%–51% and a flexural strength of 170–90 MPa were obtained. Compared with pure porous Si3N4 ceramics, the grains of porous Si3N4/BN ceramics were finer, the aspect ratio of β-Si3N4 grains was higher, and the pore size was decreased, which can be attributed to grain-boundary pinning due to BN dispersions. The relatively high flexural strength was obtained with 5% BN addition. The porous Si3N4/BN ceramics also showed low shrinkage and machinable properties.

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