Transmission electron microscopy (TEM) and scanning electron microscopy (SE
M) have been successfully used to investigate microstructures of synthetic
diamond single crystals grown from the Fe-Ni-C system under high temperatur
e and high pressure. Several types of inclusions incorporated into the diam
ond during the process of diamond growth were identified. Both the chemical
composition and structure of the inclusions in diamond were successfully d
etermined. It was found that the inclusions trapped in the diamond consiste
d of f.c.c. (FeNi)(23)C-6, orthorhombic FeSi2, f.c.c. silicon carbide and a
morphous graphite. (C) 2000 Elsevier Science S.A. All rights reserved.