Impurities identification in a synthetic diamond by transmission electron microscopy

Three types of impurities, which were trapped in diamond single crystal during process of the diamond crystal growth under high temperature and high pressure in the presence of iron–nickel solvent catalyst, have been successfully and directly investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Both the chemical composition and the crystal structure of the impurities were identified and determined. The impurities may be derived from the starting materials and the medium (pyrophillite) for transmitting the pressure, they consisted of amorphous graphite, f.c.c. (FeNi)23C6 and orthorhombic FeSi2.