Analysis of Transition Mechanism of Cubic Boron Nitride Single Crystals under High Pressure-High Temperature with Valence Electron Structure Calculation

The possibilities of hexagonal boron nitride (hBN) and lithium boron nitride (Li3BN2) transition into cubic boron nitride (cBN) under synthetic pressure 5.0 GPa and synthetic temperature 1700 K are analyzed with the use of the empirical electron theory of solids and molecules. The relative differences in electron density are calculated for dozens of bi-phase interfaces hBN/cBN, Li3BN2/cBN. These relative differences of hBN/cBN are in good agreement with the first order of approximation (), while those of Li3BN2/cBN are much greater than 10%. This analysis suggests that Li3BN2 is impossible to be intermediate phase but is a catalyst and cBN should be directly transformed by hBN.