Characterizations of several cubic phases directly transformed from the graphitic BC2N

The graphitic BC2N was transformed to cubic phases similar to diamond and cBN without any additive above 2150 degrees C under 7.7 GPa. X-ray diffraction patterns indicated that these cubic phases tended to segregate to cBN and diamond with increasing temperature to 2400 degrees C. This tendency was also supported by elemental mapping analysis of Auger electron spectroscopy (AES). Detailed spot analyses by AES, however, did not detect purl BN or C domains in the cubic crystals. This may imply that cBN grains contain tiny crystals of diamond and vice versa.