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Title: Microstructural Changes upon Milling of Graphite in Water and Subsequent MWCNT Formation During High Temperature Annealing

Abstract

The method of preparing carbon nanotube (CNT) by milling of graphite particles in water followed by high temperature annealing is proposed and the mechanism discussed. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) line broadening analysis reveal that cleavage of the graphite particles occurs preferentially along the out-of-plane {pi} bonds. Carbon K-edge near edge X-ray absorption fine structure (NEXAFS) of the milled graphite shows an increased sp3 character of the C=C bonds, but no major bonds rupture in the graphene sheets. The annealing at 1400 deg. C for 4 h of the milled graphite in argon results in formation of multiwalled carbon nanotubes accompanied with a number of coiled and twisted stacks of graphene sheets. The increased structural disorder of the milled graphite and presence of iron contaminations facilitate the rolling up of the cleaved graphene sheets during annealing.

Authors:
; ; ;  [1]
  1. College of Health and Science, University of Western Sydney, Locked Bag 1797, Penrith South DC 1797 (Australia)
Publication Date:
OSTI Identifier:
21049298
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 879; Journal Issue: 1; Conference: 9. international conference on synchrotron radiation instrumentation, Daegu (Korea, Republic of), 28 May - 2 Jun 2006; Other Information: DOI: 10.1063/1.2436335; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ANNEALING; ARGON; CHEMICAL BONDS; CLEAVAGE; CRYSTAL STRUCTURE; FINE STRUCTURE; GRAPHITE; IRON; LINE BROADENING; MILLING; NANOTUBES; PARTICLES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY

Citation Formats

Milev, Adriyan, Tran, Nguyen, Kamali Kannangara, G. S., and Wilson, Michael. Microstructural Changes upon Milling of Graphite in Water and Subsequent MWCNT Formation During High Temperature Annealing. United States: N. p., 2007. Web. doi:10.1063/1.2436335.
Milev, Adriyan, Tran, Nguyen, Kamali Kannangara, G. S., & Wilson, Michael. Microstructural Changes upon Milling of Graphite in Water and Subsequent MWCNT Formation During High Temperature Annealing. United States. doi:10.1063/1.2436335.
Milev, Adriyan, Tran, Nguyen, Kamali Kannangara, G. S., and Wilson, Michael. Fri . "Microstructural Changes upon Milling of Graphite in Water and Subsequent MWCNT Formation During High Temperature Annealing". United States. doi:10.1063/1.2436335.
@article{osti_21049298,
title = {Microstructural Changes upon Milling of Graphite in Water and Subsequent MWCNT Formation During High Temperature Annealing},
author = {Milev, Adriyan and Tran, Nguyen and Kamali Kannangara, G. S. and Wilson, Michael},
abstractNote = {The method of preparing carbon nanotube (CNT) by milling of graphite particles in water followed by high temperature annealing is proposed and the mechanism discussed. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) line broadening analysis reveal that cleavage of the graphite particles occurs preferentially along the out-of-plane {pi} bonds. Carbon K-edge near edge X-ray absorption fine structure (NEXAFS) of the milled graphite shows an increased sp3 character of the C=C bonds, but no major bonds rupture in the graphene sheets. The annealing at 1400 deg. C for 4 h of the milled graphite in argon results in formation of multiwalled carbon nanotubes accompanied with a number of coiled and twisted stacks of graphene sheets. The increased structural disorder of the milled graphite and presence of iron contaminations facilitate the rolling up of the cleaved graphene sheets during annealing.},
doi = {10.1063/1.2436335},
journal = {AIP Conference Proceedings},
number = 1,
volume = 879,
place = {United States},
year = {Fri Jan 19 00:00:00 EST 2007},
month = {Fri Jan 19 00:00:00 EST 2007}
}
  • The effects of mechanical milling (MM) on the phase transformation of graphite carbon were investigated using high resolution electron microscopy (HREM), x-ray diffraction, and differential thermal analysis (DTA). Amorphization of graphite as a result of prolonged high-energy ball milling was directly observed with HREM. The exothermic peak in the DTA trace of the {approximately}200 h ball milled sample indicated a crystallization onset temperature of about 670{degree}C and crystallization activation energy of 234 kJ/mole. {copyright} {ital 1996 Materials Research Society.}
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  • High-energy ball-milling of monoclinic ZrO{sub 2} was performed in air using the planetary ball mill with a stainless steel milling assembly. Structural and microstructural changes during the ball-milling were monitored using X-ray powder diffraction, Raman spectroscopy, Moessbauer spectroscopy, field emission scanning electron microscopy and energy dispersive X-ray spectrometry. The results of line broadening analysis indicated a decrease in the crystallite size and an increase in the microstrains with the ball-milling time increased up to {approx}150 min. The results of quantitative phase analysis indicated the presence of a very small amount of tetragonal ZrO{sub 2} phase in this early stage ofmore » ball-milling. The onset of m-ZrO{sub 2} {sup {yields}} t-ZrO{sub 2} transition occurred between 10 and 15 h of ball-milling, which resulted in a complete transition after 20 h of ball-milling. Further ball-milling caused a decrease of the t-ZrO{sub 2} lattice parameters followed by a probable transition into c-ZrO{sub 2}. It was concluded that the stabilization of t- and c-ZrO{sub 2} polymorphs at RT can be attributed to the incorporation of aliovalent cations (Fe{sup 2+}, Fe{sup 3+} and Cr{sup 3+}) introduced into the sample due to the wear and oxidation of the milling media.« less
  • We report the first study of the effect of high-energy mechanical deformation on amorphous iron-based metallic alloys. The structural changes happening in amorphous iron-based materials containing Co or Ni during mechanical deformation show that the structural stability of an amorphous alloy against a thermal and a mechanical process are not related. Therefore, the concept of a high local effective temperature during the milling process cannot be singled out as the only reason for the observed structural transformations.