Crystallization behavior of cubic boron nitride from an amorphous BN precursor via high-pressure, high-temperature treatment with controlled water addition

Takahiro Mochizuki, Yusuke Yamamoto, Naokazu Idota, Fumio Kawamura, Takashi Taniguchi, Yoshiyuki Sugahara

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Crystallization behavior of cubic boron nitride (c-BN) from amorphous boron nitride (a-BN) by high-pressure, high-temperature (HP-HT) treatment with the intentional addition of a controlled amount of water was studied. The a-BN precursor was prepared by pyrolysis of a boric acid-urea complex with urea/boric acid = 2 at 1000 °C for 3 h under an ammonia atmosphere. Hexagonal BN (h-BN) were initially crystallized from a-BN containing 2 mass% of water after HP-HT treatment at 7.7 GPa and 1200 °C, and the formation of c-BN was observed after 5 min. The crystallization of c-BN from a-BN containing 8 mass% of water after HP-HT treatment at 7.7 GPa and 1200 °C was observed even after 1 min, indicating that the crystallization of c-BN was promoted by increasing the amount of water added. In addition, since neither h-BN nor c-BN was crystallized from a-BN without intentional water addition after the same HP-HT treatment, the addition of water promoted the crystallization of both h-BN and c-BN from a-BN. Since no transformation from h-BN to c-BN was observed during HP-HT treatment at 7.7 GPa and 1200 °C, it was concluded that c-BN was directly crystallized from a-BN. After HP-HT treatment at 7.7 GPa and 1650 °C for 1 min, both h-BN and c-BN were crystallized from a-BN containing 8 mass% of water. These results clearly indicate that the addition of water has a positive effect on crystallization of c-BN from a-BN.

Original languageEnglish
Pages (from-to)3565-3569
Number of pages5
JournalJournal of the European Ceramic Society
Volume36
Issue number15
DOIs
Publication statusPublished - 2016 Nov 1

Keywords

  • Amorphous boron nitride
  • Cubic boron nitride
  • High-pressure
  • High-temperature treatment

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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