Hot pressed HfB2 and HfB2-20 vol%SiC ceramics based on HfB2 powder synthesized by borothermal reduction of HfO2

De Wei Ni, Guo-Jun Zhang, Yan-Mei Kan, Pei-Ling Wang

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Phase pure hafnium diboride (HfB2) powder was synthesized by borothermal reduction of hafnium dioxide using amorphous boron at relatively low temperature (1600°C) in vacuum. The synthesized HfB2 powder had an average particle size of 1.37 μm with an equiaxed shape, and a low oxygen content of 0.79 wt%. Using the as-synthesized HfB2 powder and a commercial SiC, HfB2 monolithic, and HfB2-20 vol%SiC composite were hot pressed at 2000°C to relative densities of 95.7% and 99.2%, respectively. With the addition of SiC, the grain size decreased and the fracture behavior changed from intergranular to a mixed mode, which resulted in a high flexural strength of 993±90 MPa for the composite. Fracture toughness of the composite was 6.29±0.65 MPa m1/2, which was significantly higher than that of the HfB2 monolithic and the reported values in literature. © 2009 The American Ceramic Society.
Original languageEnglish
JournalInternational Journal of Applied Ceramic Technology
Volume7
Issue number6
Pages (from-to)830-836
ISSN1546-542x
DOIs
Publication statusPublished - 2010
Externally publishedYes

Keywords

  • Behavioral research
  • Borides
  • Boron
  • Fracture
  • Hafnium
  • Hafnium oxides
  • Oxygen
  • Silicon carbide
  • Textures
  • Fracture toughness

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