Synthesis of dense BCx phases under high-pressure and high-temperature

Abstract

We synthesized a new phase from the B-C system, cubic BC4 (c-BC4), by direct transformation from graphitic phases at a pressure of 44 GPa and a temperature 2020 K in a laser-heated diamond anvil cell (DAC). Both x-ray diffraction and Raman spectroscopy confirm the presence of cubic BC4 from the sample recovered at ambient conditions. The zero-pressure lattice parameter of the c-BC4 calculated from diffraction peaks was found to be 3.587 Å. The composition of the new phase is determined from electron microprobe (EMP) measurements. The value of the C/B ratio is around 4 (3.91 = 0.26). © 2010 IOP Publishing Ltd.