Processing and Mechanical Properties of Zirconium Diboride-Based Ceramics Prepared by Spark Plasma Sintering

Authors

  • Hailong Wang,

    1. State Key Lab of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
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    • Key Lab of Material Physics of Ministry of Education, Zhengzhou University, Henan, China.

  • Chang-An Wang,

    Corresponding author
    1. State Key Lab of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
      †Author to whom correspondence should be addressed. e-mail: wangca@tsinghua.edu.cn
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    • *Member, American Ceramic Society.

  • Xuefeng Yao,

    1. School of Aerospace, Tsinghua University, Beijing 100084, China
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  • Daining Fang

    1. School of Aerospace, Tsinghua University, Beijing 100084, China
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  • R. Koc—contributing editor

  • This work was supported by the 973 program from Ministry of Science and Technology of China (Grant No. 5133102-4) and Tsinghua Basic research fund (Grant No. Jc2003039).

†Author to whom correspondence should be addressed. e-mail: wangca@tsinghua.edu.cn

Abstract

Zirconium diboride (ZrB2) reinforced by nano-SiC whiskers has been prepared by spark plasma sintering (SPS). Of most interest is the densification of ZrB2–SiCw composites accomplished by SPS at a temperature as low as 1550°C. The relative density of ZrB2–SiCw composites could reach to 97% with an average grain size of 2–3 μm. Both flexural strength and fracture toughness of the composites were improved with increasing amount of SiCw. Flexural strengths ranged from 416 MPa for monolithic ZrB2 to over 545 MPa for ZrB2–15 vol% SiCw composites. Similarly, fracture toughness also increased from 5.46 MPa·m1/2 to more than 6.81 MPa·m1/2 in the same composition range. The relative density of ZrB2–SiCw composites could be further improved to near 100% by adding some sintering aids such as AlN and Si3N4; however, the effects of different sintering additives on the mechanical properties of the composites were different.

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