Heat resistance of a shock-synthesized B–C–N heterodiamond

Abstract

The heat resistance of a B–C–N heterodiamond (c-BC_2.5N) has been investigated and compared with that of the starting material (h-BC_2.5N), graphite, diamond, c-BN and h-BN. With regard to thermogravimetry c-BC_2.5N showed partial pyrolysis up to 1300 °C and its thermal oxidation resistance lay between that of diamond and c-BN. The TG-residue of c-BC_2.5N contained significant amounts of unchanged c-BC_2.5N. This was due to coverage of c-BC_2.5N by pyrolytically produced B₂O₃. The structure transition temperatures of the three cubic materials were in the range 1800–2000 °C at atmospheric pressure and increased in the order: c-BN ≲ C-BC_2.5N < diamond. These characteristics of c-BC_2.5N can be related to its diamond-type structure composed of hetero atoms.