Linked Life Data

15361581

Source:http://linkedlifedata.com/resource/pubmed/id/15361581

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
38
pubmed:dateCreated
2004-9-22
pubmed:abstractText
A quenchable superhard high-pressure carbon phase was synthesized by cold compression of carbon nanotubes. Carbon nanotubes were placed in a diamond anvil cell, and x-ray diffraction measurements were conducted to pressures of approximately 100 GPa. A hexagonal carbon phase was formed at approximately 75 GPa and preserved at room conditions. X-ray and transmission electron microscopy electron diffraction, as well as Raman spectroscopy at ambient conditions, explicitly indicate that this phase is a sp(3)-rich hexagonal carbon polymorph, rather than hexagonal diamond. The cell parameters were refined to a(0) = 2.496(4) A, c(0) = 4.123(8) A, and V(0) = 22.24(7) A (3). There is a significant ratio of defects in this nonhomogeneous sample that contains regions with different stacking faults. In addition to the possibly existing amorphous carbon, an average density was estimated to be 3.6 +/- 0.2 g/cm(3), which is at least compatible to that of diamond (3.52 g/cm(3)). The bulk modulus was determined to be 447 GPa at fixed K' identical with 4, slightly greater than the reported value for diamond of approximately 440-442 GPa. An indented mark, along with radial cracks on the diamond anvils, demonstrates that this hexagonal carbon is a superhard material, at least comparable in hardness to cubic diamond.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
101
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13699-702
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
A quenchable superhard carbon phase synthesized by cold compression of carbon nanotubes.
pubmed:affiliation
Los Alamos National Laboratory, Los Alamos, NM 87545, USA. z_wang@lanl.gov
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.