Free Access
Microsc. Microanal. Microstruct.
Volume 6, Number 1, February 1995
Page(s) 127 - 139
Microsc. Microanal. Microstruct. 6, 127-139 (1995)
DOI: 10.1051/mmm:1995113

An EELS and XAS Study of Cubic Boron Nitride Synthesized under High Pressure - High Temperature Conditions

Michel Jaouen1, Gilles Hug2, Valérie Gonnet3, Gérard Demazeau3 et Gérard Tourillon4

1  Laboratoire de Métallurgie Physique, URA 131 du CNRS, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France
2  Laboratoire d'Etudes des Microstructures, CNRS-ONERA, B.P. 72, 92322 Châtillon Cedex, France
3  Laboratoire de Chimie du Solide du CNRS, UPR 8661 du CNRS, 351, cours de la Libération, 33405 Talence Cedex, France
4  Laboratoire d'Utilisation du Rayonnement Electromagnétique, CNRS, CEA, MEN, Centre Universitaire de Paris Sud, Bât. 209D, 91405 Orsay Cedex, France

Cubic Boron Nitride (c-BN) single-crystals have been synthesized under high pressure and high temperature conditions (HP - HT) using hexagonal Boron Nitride (h-BN) precursors. We have performed a study of both phases with electron (EELS) and X-ray (XAS) spectroscopy that are compared. The c-BN ELNES spectra at B-K and N-K edges are found to be consistent with the XANES (XAS) data, although the energy resolution achieved with X-rays is better than that obtained by EELS with a $\rm LaB_6$ filament. However, XAS is at a disadvantage by comparison with EELS owing to the presence of the N-K edge second order. Attempts were made to dope c-BN with carbon atoms. The examination of the EELS spectra reveals that the incorporation of carbon species in the BN material is always accompanied by the addition of oxygen. Several samples were analyzed both with selected area electron diffraction and energy loss spectroscopy. Most probed crystals containing C (and therefore O) were found to be hexagonal. These results emphasized that the range of existence of the cubic phase is very narrow around the binary composition.

7920K - Other electron surface impact phenomena.
7870D - X ray absorption and absorption edges condensed matter.
6180M - Channelling, blocking and energy loss of particles.
6250 - High pressure and shock wave effects in solids and liquids.

Key words
boron compounds -- electron diffraction -- electron energy loss spectra -- high pressure effects -- high temperature effects -- XANES -- EELS study -- XAS study -- high pressure conditions -- high temperature conditions -- single crystals -- X ray spectroscopy -- ELNES spectra -- XANES -- selected area electron diffraction -- cubic phase -- binary composition -- BN

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