Nanotube growth during annealing of mechanically milled Boron

Boron powder, finely ground in a tungsten carbide ball mill in an ammonia atmosphere, has been annealed at 1200 C in flowing nitrogen to produce small quantities of cylindrical BN nanotubes, both as isolated individuals and grouped into ropes. Thick-walled conical BN tubes are abundant in specimens...

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Bibliographic Details
Published inApplied physics. A, Materials science & processing Vol. 76; no. 1; pp. 107 - 110
Main Authors Fitz Gerald, J.D., Chen, Y., Conway, M.J.
Format Journal Article
LanguageEnglish
Published 01.01.2003
Subjects
Annealing
Boron
Boron nitride
Materials science
Nanocomposites
Nanomaterials
Nanostructure
Surface diffusion
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Summary:Boron powder, finely ground in a tungsten carbide ball mill in an ammonia atmosphere, has been annealed at 1200 C in flowing nitrogen to produce small quantities of cylindrical BN nanotubes, both as isolated individuals and grouped into ropes. Thick-walled conical BN tubes are abundant in specimens annealed for longer times, and their growth was catalysed once WC debris was converted into W metal particles. Some catalytic effect of small W nanoparticles could be necessary for nanotube formation, though no tip particles have been imaged here. Given the low temperature of mechanical milling and annealing, BN growth must involve surface diffusion and solid-state reconfiguration. It could be possible to engineer desirable physical and chemical properties by exploiting the variation in cylindrical versus conical BN structures as a function of annealing time.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:0947-8396
1432-0630
DOI:10.1007/s00339-002-1441-5