Simultaneous crystallization of diamond and cubic boron nitride from the graphite relative BC[sub 2]N under high pressure/high temperature conditions

Journal Article · Sat May 01 00:00:00 EDT 1993 · Chemistry of Materials; (United States)

DOI:https://doi.org/10.1021/cm00029a020· OSTI ID:6253343

Sasaki, Takayoshi; Akaishi, Minoru; Yamaoka, Shinobu; Fujiki, Yoshinori; Oikawa, Tetsuo ^[1]

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1. National Institute for Research in Inorganic Materials, Ibaraki (Japan)

Graphite BC[sub 2]N has been compressed with Co metal at a pressure of 5.5 GPa and temperatures of 1400-1600[degrees]C. The principal resulting products were crystals (average dimension 3 [mu]m) with cubiclike facets. The powder X-ray diffraction pattern revealed two kinds of cubic phase, in approximately equal amounts, which were identified as diamond and cBN on the basis of their lattice parameters. Microelemental analyses on individual crystal fragments by K-edge electron energy-loss spectroscopy confirmed this disproportionating crystallization scheme: half of the grains were composed of carbon-only signals of which gave fine-structure characteristic of sp[sup 3] bonding and the other half gave spectra characteristic of sp[sup 3] boron and nitrogen. The crystallization of cBN as well as diamond in the catalytic solvent of pure Co metal is observed here for the first time and is of relevance to the mechanism of the accepted catalytic action of cobalt on the hexagonal/cubic transformation. 26 refs., 4 figs., 2 tabs.

• OSTI ID: 6253343
• Journal Information: Chemistry of Materials; (United States), Vol. 5:5; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON NITRIDES
CRYSTALLIZATION
DIAMONDS
BONDING
CUBIC LATTICES
ENERGY-LOSS SPECTROSCOPY
FINE STRUCTURE
GRAPHITE
HEXAGONAL LATTICES
LATTICE PARAMETERS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 1000-4000 K
VERY HIGH PRESSURE
X-RAY DIFFRACTION
BORON COMPOUNDS
CARBON
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTAL MINERALS
ELEMENTS
FABRICATION
JOINING
MINERALS
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
PHASE TRANSFORMATIONS
PNICTIDES
SCATTERING
SPECTROSCOPY
TEMPERATURE RANGE
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360601 - Other Materials- Preparation & Manufacture