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Title: Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air

Abstract

We report a direct conversion of hexagonal boron nitride (h-BN) into pure cubic boron nitride (c-BN) by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN). The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.

Authors:
;  [1]
  1. Department of Materials Science and Engineering, Centennial Campus, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)
Publication Date:
OSTI Identifier:
22499247
Resource Type:
Journal Article
Journal Name:
APL Materials
Additional Journal Information:
Journal Volume: 4; Journal Issue: 2; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2166-532X
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMBIENT TEMPERATURE; BORON NITRIDES; LIQUIDS; MELTING; NUCLEATION; PHASE DIAGRAMS; QUENCHING

Citation Formats

Narayan, Jagdish, and Bhaumik, Anagh. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air. United States: N. p., 2016. Web. doi:10.1063/1.4941095.
Narayan, Jagdish, & Bhaumik, Anagh. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air. United States. https://doi.org/10.1063/1.4941095
Narayan, Jagdish, and Bhaumik, Anagh. 2016. "Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air". United States. https://doi.org/10.1063/1.4941095.
@article{osti_22499247,
title = {Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air},
author = {Narayan, Jagdish and Bhaumik, Anagh},
abstractNote = {We report a direct conversion of hexagonal boron nitride (h-BN) into pure cubic boron nitride (c-BN) by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN). The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.},
doi = {10.1063/1.4941095},
url = {https://www.osti.gov/biblio/22499247}, journal = {APL Materials},
issn = {2166-532X},
number = 2,
volume = 4,
place = {United States},
year = {Mon Feb 01 00:00:00 EST 2016},
month = {Mon Feb 01 00:00:00 EST 2016}
}