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Studies of Small Inclusions in Synthetic Diamonds by Optical Microscopy, Microradiography and Transmission Electron Microscopy
Author(s) -
Lang A. R.,
Vincent R.,
Burton N. C.,
Makepeace A. P. W.
Publication year - 1995
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889895007370
Subject(s) - transmission electron microscopy , electron microscope , microscopy , materials science , optical microscope , scanning confocal electron microscopy , dark field microscopy , optics , energy filtered transmission electron microscopy , scanning transmission electron microscopy , crystallography , chemistry , nanotechnology , scanning electron microscope , physics
A combination of low‐resolution and high‐resolution techniques was applied to establish the composition, crystallography and distribution of small inclusions, average diameters ~1 μm, dispersed within large synthetic diamonds. Both metallic and silicate phases were present among included bodies, often lying adjacent in the same cavity within the diamond matrix. Monochromatic X‐ray microradiography, achieving 1 μm resolution with Cu Kα radiation, demonstrated that transition‐metal phases constituted a minor fraction of the total volume of inclusions present. In a specimen rich in dispersed inclusions, the sizes of 1483 inclusions were individually measured. In aggregate they occupied ~4 × 10 −4 of the diamond volume. High local inclusion concentrations were associated with high local concentrations of substitutional nitrogen impurity in the diamond matrix. The electron‐microscopic techniques included convergent‐beam electron diffraction, energy‐dispersive X‐ray spectroscopy and electron‐energy‐loss spectroscopy. Detailed crystallographic identifications of individual particles included a b.c.c. Fe–Co alloy ( a 0 ≃ 2.86 Å), a garnet of andradite variety [ a 0 = 11.95 (5) Å] and a clinopyroxene with composition corresponding to that in the augite‐ferroaugite division of pyroxenes.