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.
- Publication:
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APL Materials
- Pub Date:
- February 2016
- DOI:
- 10.1063/1.4941095
- Bibcode:
- 2016APLM....4b0701N