Transformation of diamond to fullerene-type onions at pressure 70 GPa and temperature 2400 K.
Nanotechnology
; 31(31): 315602, 2020 Jul 31.
Article
em En
| MEDLINE
| ID: mdl-32315987
ABSTRACT
We report the observation of a phase transition of diamond to denser than diamond carbon phase composed from 2 to 3 fullerene-type shells of onions. Raman spectra indicate the fullerene-type of the onions shells. The onions phase is a stable phase in a diamond instability zone of a phase diagram of carbon at pressure 70 GPa and temperature 2400 K. A mixture of diamond and Ni powders was heated by a laser beam under pressure in a diamond anvil cell. Both direct and catalytic diamond to onions transitions were observed during heating. The catalytic transformation includes the following steps. Melting of Ni during the laser heating at pressure 70 GPa, a 'diamond solution' (a transfer of carbon atoms from diamond) in liquid Ni and the formation of an equilibrium carbon phase from the supersaturated solution upon cooling. The catalytic process is a reverse one relative to the catalytic synthesis of diamond in a diamond stability zone at pressure around 6 GPa. The main result of our study is the presence of fullerene-type structures in the phase diagram of carbon in the region of diamond instability under high sub-Mbar pressure and wide range of temperatures.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Nanotechnology
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Federação Russa