Titre :

Nanodiamond nucleation below 2273K at 15GPa from carbons with different structural organizations

Auteur(s) :

Le Guillou, Corentin [Auteur]
Laboratoire de géologie de l'ENS [LGENS]
Brunet, Fabrice [Auteur]
Laboratoire de géologie de l'ENS [LGENS]
Irifune, Tetsuo [Auteur]
Ohfuji, Hiroaki [Auteur]
Rouzaud, Jean-Noël [Auteur]
Laboratoire de géologie de l'ENS [LGENS]

Titre de la revue :

Carbon

Nom court de la revue :

Carbon

Numéro :

45

Pagination :

636-648

Éditeur :

Elsevier BV

Date de publication :

2007-03

ISSN :

0008-6223

Discipline(s) HAL :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

Résumé en anglais : [en]

Five precursors covering the whole range of carbon structural organization, i.e. a quasi-amorphous soot (QAS), a raw carbon black (CB), a carbon black heat-treated at 2600 C (HTCB), a polycrystalline graphite (PCG) and a ...
Lire la suite >Five precursors covering the whole range of carbon structural organization, i.e. a quasi-amorphous soot (QAS), a raw carbon black (CB), a carbon black heat-treated at 2600 C (HTCB), a polycrystalline graphite (PCG) and a highly oriented pyrolytic-graphite (HOPG) were run at 15 GPa in the 1500–1900 C range between 15 and 60 min. Full transformation into nano-diamonds was not always achieved and the corresponding run products preserved the tracks of the transformation mechanisms which led to diamond formation. These mechanisms and their kinetics were characterized combining X-ray powder diffraction, Raman micro-spectroscopy and high-resolution TEM. Globally, the disordered precursors react faster than the crystalline ones: they achieve higher transformation rates and become transparent more easily. For the spherical CB particles, nano-diamond preferentially nucleates in their centre. The graphitic layers in the QAS directly transform into diamond without any prior graphitization. The crystalline organization is even found to decrease for the graphitized precursors (HTCB and PCG) as evidenced by HRTEM images showing graphite delamination. These precursors mostly evolve according to a diffusion-limited reconstructive mechanism which initiates at the precursor structural defects. HOPG behaves differently since it mostly transforms into lonsdaleite rather than cubic diamond.Lire moins >

Langue :

Anglais

Audience :

Non spécifiée

Collections :

• Autres travaux scientifiques

Date de dépôt :

2019-06-19T12:45:42Z
2019-06-27T09:46:13Z
2019-06-27T09:50:59Z
2019-06-28T13:14:24Z