Structural features of pyrocarbon atomistic models constructed from transmission electron microscopy images
Langue
EN
Article de revue
Ce document a été publié dans
Carbon. 2012-10-01, vol. 50, n° 12, p. 4388-4400
Résumé en anglais
We report on atomistic models of laminar pyrocarbons constructed using a combination of 2D high resolution transmission electron microscopy (HRTEM) lattice fringe image analysis, 3D image synthesis and atomistic simulated ...Lire la suite >
We report on atomistic models of laminar pyrocarbons constructed using a combination of 2D high resolution transmission electron microscopy (HRTEM) lattice fringe image analysis, 3D image synthesis and atomistic simulated annealing. In a first step, the effectiveness of the method and the convergence of the models with respect to the quench rate are checked on small systems. Then, the nanostructural features of large fully carbonaceous atomistic models obtained from the HRTEM images of a rough laminar pyrocarbon, asprepared and after partial graphitization, are discussed. Both models show a very pronounced sp2 character (≥ 97%), essentially made of hexagonal rings (≥ 88%) and pentagonal and heptagonal rings in similar amounts (≈ 6%). The latter mostly form pentagon-heptagon pairs or networks of line defects between misoriented hexagonal domains. Numerous pairs of screw dislocations, connecting different graphene domains, are also observed while edge dislocations with unsaturated carbon atoms are almost absent. The models are validated with respect to experimental pair distribution functions, showing excellent agreement.< Réduire
Mots clés en anglais
Porous carbons
Microstructure
Simulation
Nanostructure
Diffraction
Statistics
Project ANR
Matrices de Pyrocarbone à l'échelle nanométrique: Caractérisation – Modèles – Propriétés - ANR-10-BLAN-0929