title: Decomposition of Fe5C2catalyst particles in carbon nanofibers during TEM observation.
abstract: The effect of an electron beam on nanoparticles of two Fe carbide catalysts inside a carbon nanofiber was investigated in a transmission electron microscope. Electron beam exposure does not result in significant changes for cementite (θ-Fe3C). However, for Hägg carbide nanoparticles (χ-Fe5C2), explosive decay is observed after exposure for 5-10 s. This produces small particles of cementite and γ-Fe, each covered with a multilayer carbon shell, and significantly modifies the carbon-fiber structure. It is considered that the decomposition of Hägg carbide is mostly due to the damage induced by high-energy electron collisions with the crystal lattice, accompanied by the heating of the particle and by mechanical stress provided by the carbon layers of the nanofiber.
authors.affiliation: Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk 142190, Moscow region, Russia.
authors.forename: Vladimir D
authors.initials: VD
authors.lastname: Blank
authors.affiliation: Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk 142190, Moscow region, Russia.
authors.forename: Boris A
authors.initials: BA
authors.lastname: Kulnitskiy
authors.affiliation: Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk 142190, Moscow region, Russia.
authors.forename: Igor A
authors.initials: IA
authors.lastname: Perezhogin
authors.affiliation: Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk 142190, Moscow region, Russia.
authors.forename: Yuriy L
authors.initials: YL
authors.lastname: Alshevskiy
authors.affiliation: Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk 142190, Moscow region, Russia.
authors.forename: Nikita V
authors.initials: NV
authors.lastname: Kazennov
keywords: HRTEM; carbon nanofiber; electron beam; iron carbide