Densification and microstructure of Al2O3-cBN composites prepared by spark plasma sintering

Mikinori Hotta, Takashi Goto

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65 Citations (Scopus)


Al2O3-cubic boron nitride (cBN) composites were prepared from Al2O3 and cBN powders by spark plasma sintering (SPS) at temperatures of 1200 to 1600°C for 600 s under a pressure of 100 MPa. Densification, phase transformation, microstructure and mechanical properties of the Al2O3-cBN composites were investigated. Fully dense Al2O3-cBN composites containing 10 to 20 vol% cBN with a relative density of more than 98% were obtained at 1300°C for 600 s without the phase transformation from cBN to hexagonal BN (hBN). The transformation of cBN was more greatly accelerated in the Al2O 3-cBN composite than in cBN. The cBN phase to Al2O 3 inhibited the grain growth of Al2O3 in the Al2O3-cBN composite. Vickers hardness of dense Al 2O3-cBN composites containing 10 to 20 vol% cBN sintered at 1300°C showed the maximum value of 26 GPa. The Al2O 3-cBN composite containing 20 vol% cBN sintered at 1300°C had the highest fracture toughness of 4.1 MPa.m1/2.

Original languageEnglish
Pages (from-to)744-748
Number of pages5
JournalJournal of the Ceramic Society of Japan
Issue number1354
Publication statusPublished - 2008 Jun


  • Alumina
  • Composite
  • Cubic boron nitride
  • Cutting tools
  • Densification
  • Microstructure
  • Spark plasma sintering

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry


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