TEM investigation on micro-inclusions and dislocations in a HPHT-grown diamond single crystal from Ni-C system

In this paper, microstructures of diamond single crystal grown from Ni-C sy stem under high temperature and high pressure (HPHT) were examined by trans mission electron microscopy (TEM). it was shown that there exist growth def ects such as micro-inclusions, dislocation networks, an array of dislocatio ns and dislocation pileup in the diamond The formation process and characte ristics of these defects were analyzed briefly. The micro-inclusions are co mposed of hexagonal Ni3C, hexagonal SiO2 and amorphous graphite, which may be derived from the starting materials and the medium (pyrophyllite) for tr ansmitting the pressure. The dislocations are related to internal stress in the diamond, which may be correlative with the micro-inclusions in the dia mond.