A New Cubic B-C-N Compound Revealed by High-Resolution Analytical Electron Microscopy

A new cubic B-C-N compound has been characterized by means of high-resolution analytical electron microscopy. The specimens prepared from graphitic BC2N at a high pressure of 7.7 GPa and a temperature of 2,300°C for 15 min contained a mixture of small crystals of cubic B-C-N, diamond and cubic BN. The result of both electron diffraction and high resolution lattice image revealed that the B-C-N crystal had a cubic symmetry having a diamond-type structure. An electron energy loss spectra obtained from about 1 nm area suggested that the chemical composition of the crystal was close to BC2N. The fine structures of the spectra also indicated that the crystal was not a graphitic- but a diamond-type. It was also observed that the cubic B-C-N transformed into the graphitic B-C-N due to an intense electron beam irradiation.