ormation of Nanosized Inclusions in Cubic Boron Nitride Single Crystals

Cubic boron nitride (c-BN) crystals with dimensions of 0.3-0.4 mm, which have been synthesized using lithium nitride (Li₃N) as a catalyst with a high-pressure high-temperature method, were examined by transmission electron microscopy (TEM). The TEM result shows that there exits some nanostructrued areas containing several types of nanosized foreign particles within the as-grown c-BN crystals. We find that the nanometer inclusions are hexagonal BN with the lattice constants of a = 2.054Å and c = 6.66Å, tetragonal B₂₅N with a = 8.79Å and c = 5.08Å, tetragonal B₅₃N with a = 8.79Å and c = 5.08Å, and hexagonal Li₃N with a = 3.648Å and c = 3.875Å.