The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nanometers (807 Ni atoms). A tight binding model for interatomic interactions drives the Grand Canonical Monte Carlo simulations used to locate solid, core/shell and liquid stability domains, as a function of size, temperature and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should be taken into account in our understanding of the nanotube growth mechanisms.
@article{arxiv.1504.06193,
title = {Size dependent phase diagrams of Nickel-Carbon nanoparticles},
author = {Yann Magnin and Alexandre Zappelli and Hakim Amara and François Ducastelle and Christophe Bichara},
journal= {arXiv preprint arXiv:1504.06193},
year = {2015}
}