Thermal stability of Al 3 BC 3 powders under a nitrogen atmosphere

The thermal stability of Al 3 BC 3 powders under nitrogen was studied. AlN–BN composites were generated during the nitridation of Al 3 BC 3 . Possible reaction mechanisms responsible for the thermal decomposition of Al 3 BC 3 powders were discussed. The relatively weaker Al–C bonds in Al 3 BC 3 promoted the fast diffusion of Al and the generation of AlN–BN layers inhibited the deeper nitridation, thus the thermal decomposition was governed by surface reaction. The formed nitrides resulted in a volume change and cracked the resulting layers as the reactions progressed, facilitating the diffusion of N 2 and enhanced the decomposition of Al 3 BC 3 . The intensive reaction involving Al 3 BC 3 and N 2 could be attributed to the prolonged reaction time at high temperature and continued escape of vaporized Al and B. This result contributes to a theoretical basis of high-temperature application of Al 3 BC 3 under nitrogen.