Thermal stability of Al₃BC₃ powders under a nitrogen atmosphere

The thermal stability of Al3BC3 powders under nitrogen was studied. AlN-BN composites were generated during the nitridation of Al3BC3. Possible reaction mechanisms responsible for the thermal decomposition of Al3BC3 powders were discussed. The relatively weaker Al-C bonds in Al3BC3 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 Al3BC3. The intensive reaction involving Al3BC3 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 Al3BC3 under nitrogen.