Synthesis of Boron-Rich Cubic B(C_xN_1-x) Compounds

B₂CN precursor is prepared by a mechanical vibration-milling process using amorphous boron, graphite and h-BN powders with mole ratio of 1:1:1. A mixture of precursor and Ca₃B₂N₄ catalyst is treated under high pressure and high temperature. A boron rich cubic B(C_xN_1-x) phase is obtained after removing the catalyst by acid treatment. The average C content of the boron-rich cubic phase is about 6 at.% detected by energy-dispersive x-ray analysis spectroscopy. It is found that the highest carbon content in the cubic phase is as large as 16 at.%.