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

The heat resistance of a B-C-N heterodiamond (c-BC2.5N) has been investigated and compared with that of the starting material (hBC(2.5)N), graphite, diamond, c-BN and h-BN. With regard to thermogravimetry c-BC2.5N showed partial pyrolysis up to 1300 degrees C and its thermal oxidation resistance lay between that of diamond and c-BN. The TO-residue of c-BC2.5N contained significant amounts of unchanged c-BC2.5N. This was due to coverage of c-BC2.5N by pyrolytically produced B2O3. The structure transition temperatures of the three cubic materials were in the range 1800-2000 degrees C at atmospheric pressure and increased in the order: c-BN less than or similar to C-BC2.5N < diamond. These characteristics of c-BC2.5N can be related to its diamond-type structure composed of hetero atoms.