View in EDS

Transformations of the amorphous and crystalline modifications of fullerene C70 under high pressures and high temperatures.

Saved in:
Bibliographic Details
Title: Transformations of the amorphous and crystalline modifications of fullerene C70 under high pressures and high temperatures.
Authors: Borisova, P.A.1, Blanter, M.S.2 mike.blanter@gmail.com, Brazhkin, V.V.3, Lyapin, S.G.3, Somenkov, V.A.1, Filonenko, V.P.3, Trenikhin, M.V.4, Presniakov, M.Yu.1
Source: Diamond & Related Materials. May2018, Vol. 85, p74-79. 6p.
Subjects: Fullerenes, Phase transitions, Graphite, Amorphous substances, High temperatures
Abstract: Phase transformations of the amorphous phase of fullerene C 70 at high temperature (HT) (up to 1100 °C) and high pressure (HP) (2–8 GPa) have been investigated and compared with the previous studies on the crystalline phase of fullerene C 70 . The amorphous phase of fullerene C 70 was obtained by ball-milling. The study was conducted using neutron diffraction, Raman spectroscopy and HRTEM. It was shown that under the influence of HT and HP, the amorphous-like phase of fullerene C 70 retains an amorphous structure up to 500 °C and transforms аt temperatures 800–1100 °C into amorphous-like or nanocrystalline graphite. The interesting difference of the transformation of the amorphous and crystalline phases of C 70 is the structure of formed amorphous-like graphite. These types of amorphous-like graphite differ in the type of neutron diffraction patterns and in the presence or absence of graphite nanoclusters. An explicit anisotropy of amorphous-like graphite is revealed, which is manifested in the dependence of the diffraction patterns on the direction of measurement of the diffraction pattern in the sample under study. The introduction of deuterium affects the structure and diffraction spectra of amorphous-like graphite formed at HTHP. [ABSTRACT FROM AUTHOR]
Copyright of Diamond & Related Materials is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:Phase transformations of the amorphous phase of fullerene C 70 at high temperature (HT) (up to 1100 °C) and high pressure (HP) (2–8 GPa) have been investigated and compared with the previous studies on the crystalline phase of fullerene C 70 . The amorphous phase of fullerene C 70 was obtained by ball-milling. The study was conducted using neutron diffraction, Raman spectroscopy and HRTEM. It was shown that under the influence of HT and HP, the amorphous-like phase of fullerene C 70 retains an amorphous structure up to 500 °C and transforms аt temperatures 800–1100 °C into amorphous-like or nanocrystalline graphite. The interesting difference of the transformation of the amorphous and crystalline phases of C 70 is the structure of formed amorphous-like graphite. These types of amorphous-like graphite differ in the type of neutron diffraction patterns and in the presence or absence of graphite nanoclusters. An explicit anisotropy of amorphous-like graphite is revealed, which is manifested in the dependence of the diffraction patterns on the direction of measurement of the diffraction pattern in the sample under study. The introduction of deuterium affects the structure and diffraction spectra of amorphous-like graphite formed at HTHP. [ABSTRACT FROM AUTHOR]
ISSN:09259635
DOI:10.1016/j.diamond.2018.04.001