Synthesis of Novel Al2O3-Mullite-cBN Composites from a Mixture of Al2O3 with SiO2 Nanolayer Coated cBN by Rotary CVD and Spark Plasma Sintering

Xin Zhang, Jianfeng Zhang, Takashi Goto, Yuping Wu

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

In the present study, novel Al2O3-mullite-cBN composites were synthesized from a mixture of Al2O3 and SiO2 coated on cBN (cBN/SiO2) by spark plasma sintering. SiO2 nanolayer was coated on cBN powder (cBN/SiO2) by rotary CVD using tetraethyl orthosilicate as a precursor and O2 as a reactive gas. The thickness of SiO2 nanolayer (TSSiO2) increased from 32 to 52 nm with increasing FO2 from 0 to 0.42×10−6 m3.s−1, and then decreased to 25 nm with increasing FO2 to 0.42×10−6 m3.s−1. The cBN/SiO2 powder was mixed with Al2O3 and consolidated by spark plasma sintering at 1473–1873 K for 0.6 ks. A uniform mullite (Al6Si2O13) phase was formed at 1673 K by the reaction of SiO2 nanolayer with Al2O3. At a sintering temperature of 1573 K and TSSiO2=52 nm, the relative density and the hardness of Al2O3-mullite-cBN was 97% and 24.9 GPa, respectively. The obtained hardness was about 3.9 GPa higher than that of monolithic Al2O3, 12.4 GPa higher than that of SiO2-cBN, and 8.9 GPa higher than that of SiAlON-cBN and mullite-cBN composites, suggesting that the as-obtained Al2O3-mullite-cBN composites could be possibly used for cutting and wear resistant applications.

Original languageEnglish
Pages (from-to)148-151
Number of pages4
JournalTransactions of the Indian Ceramic Society
Volume74
Issue number3
DOIs
Publication statusPublished - 2015 Jul 3

Keywords

  • Cubic boron nitride (cBN)
  • Densification
  • Rotary CVD
  • SiO nanolayer
  • Spark plasma sintering

ASJC Scopus subject areas

  • Ceramics and Composites

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